We are Moving

3SL are Moving Offices

Moving office
Moving office

As of 30th May 2024, 3SL have a new office address:

College House
Howard Street
LA14 1NB

Our phone number and email addresses will remain the same.

Please can we ask that you update your records accordingly.

We apologise if you have noticed any connectivity issues with 3SL services and/or downtime with the 3SL website/email. Everything is now back up and running.

From the 3SL team

Circus Starr

Supporting Circus Starr

3SL are proud to announce that we are supporting Circus Starr!

Circus Starr
Circus Starr

The community interest company are dedicated to making a difference to the lives of vulnerable and disadvantaged children in Barrow-in-Furness and across England through the magical art of circus. We are pleased to support our community, and this accessible and inclusive event is such a worthy cause.

Circus Star
Circus Star

To find out more about how you can support the circus with a purpose visit www.circus-starr.org.uk or call +44 (0) 1260 288690.

Cyber Essentials and IASME/GDPR Assessment 2020

Cyber Essentials Assessment

Structured Software Systems Limited (3SL)  are happy to say that we have been successful in our re-assessment under the Cyber Essentials

scheme for another year.

Cyber Essentials Badge
Cyber Essentials Badge

Cyber Essentials is a Government-backed, industry-supported scheme to help organisations protect themselves against common online threats.

IASME Assessment

Assessment for the IASME standard including GDPR were also successfully renewed.


The IASME Governance standard, based on international best practice, is risk-based and includes aspects such as physical security, staff awareness, and data backup. It is recognised as the best cyber security standard for small companies by the UK Government when in consultation with trade associations and industry groups.

Best Practice

We believe this sort of assessment will give our customers confidence when dealing with 3SL.  It is a good reality check, and we would encourage our customers use similar precautions for their businesses. Whilst these assessments can provide confidence in your data security, the unexpected may happen. Whether this is a malicious attack, or simply  a power loss and failure of your UPS resulting in disk corruption. Alongside good data security, we would also recommend you always have a good backup plan for your Cradle data.

Further Reading

The Cyber Essentials

  • Introduction
  • Standard
Cyber Essentials Logo
Cyber Essentials

Season’s Greetings 2019

Season’s Greetings from 3SL

节日祝福, С Новым годом и Рождеством, Saudações da temporada, Prettige Feestdagen, Frohe Festtage, Cyfarchion y Tymor, 계절의 인사, Joyeuses Fêtes.

3SL Christmas star - Based on Photo by Nick Collins from Pexels
3SL Star

Whatever your beliefs and however you celebrate the end of 2019, 3SL would like to wish all its customers, potential customers, distributors, partners and staff, Season’s Greetings, a Happy Christmas and peaceful family times over the festive season. We’ll see you again in the new year.

The UK offices will be closed, from end of business on Tuesday 24th December to 2nd January 2020. During that time there will be no one manning the phones. However, you can send support enquiries to support@threesl.com and we’ll deal with them as soon as we can.

Privacy Policy – Update May 2018

Information We Collect and How we Use It


Under the new GDPR (General Data Protection Regulations) we’ve updated our (Structured Software Systems Limited – 3SL)  Privacy Policy.

This sets out how we we deal with your information, and how you can get in touch with us.

We fully intend to keep in touch with all our customers, and prospects for which we have a legitimate business interest, or a need to service your contract.

If you believe you no longer fall into these categories, please use the un-subscribe link on any of our emails or write to us at our UK Headquarters www.threesl.com/contact or email  privacy@threesl.com.

A man walked into a coffee shop to order himself a drink.

Barista said “Wha’ d’ you want?”, before he’d had time to think.

“I’ll take a cappuccino, please, with sprinkles and a sugar or two”

“No prob’s I’ll have that in a jiffy, ready and tasty for you.
Just so I can make sure, you get your chosen drink,
I’ll need your name upon this cup, he said without a blink.

“That’s personally identifiable information, mate, which is mine to keep.
But if I know you’ll handle it right, a soundly I will sleep.
Can you show me your Privacy Policy, that’s in-line with GDPR,
if you can’t I’ll go to the drive-through down the road, in my little car”

The policy was provided, all typed up and neat,
All twenty six pages of it, hardly what you’d call a treat.
At the end the man was happy his named cup in bold,
would be retained no longer than necessary, but by then, his coffee, was cold!



Whoooosh – Download from 3SL even faster!

Faster Fibre Connection

3SL (Structured Software Systems Limited)  are pleased to announce a new dedicated ‘fibre to the premises’ (FTTP) link to 3SL Headquarters, here in the UK.

We now have a 100 MBits/sec bi-directional connection to the ether, some five times faster than the previous contract fibre! Go on – give it a go, download one of our white papers, or the latest version of Cradle.

faster fibre illustration, based on images from pexels.com and unsplash.com
Faster Fibre

We’re happy to say our ISP services are still provided by Zen Internet, it’s just the new transport mechanism installed by BT can support better transfer rates. So wherever you are in the world, you can reach us here in Barrow-in-Furness at the edge of the English Lake District in Cumbria.


3SL Email Filters

We all use e-mail as a reliable method for our personal and business communications. However, as we all know, vast numbers of spam, junk and malicious e-mails are also sent every day. Everyone needs protection from the damage that clicking a link or attachment in just one e-mail can do. 3SL has recently changed our 3SL email filters to further reduce our exposure to such threat vectors. We expect that you and your organisation also update your filters regularly.

3SL email filters
Block Spam and Malicious E-Mails

This blog post is a summary of what the 3SL email filters will do.

We are publishing this so that you can reliably send your emails to us. We do not expect that the 3SL email filters will block any of your emails. But if one of your emails is blocked, this blog post may help to explain why.

Principles of 3SL Email Filters

We will obviously not disclose full details of the 3SL email filters. You would not expect us to do something that silly. There are some general principles which we will publish, which are:

  • The more malicious an email is, the less likely our mail server is to provide an informative response to the sender, or their mail server
  • The more malicious an email is, the more likely we are to provide false responses, or no response, to the sending mail server
  • We use all available blacklists to ignore all known malicious senders and mail relays. Either we access them online, or we keep local copies and then update them regularly.
  • 3SL always reports malicious financial emails to the organisation that they are supposed to come from
  • We report all malicious e-mails to blacklist sites wherever possible
  • We automatically block emails based on their from, to, subject, content, formatting and attachments
  • Any e-mails sent to undisclosed recipients or with multiple from tags will be rejected
  • We operate our own blacklists, for people we dislike
  • Emails from people we especially dislike are automatically sent to spam reporting sites
  • We operate our own whitelists, for people we like!
  • All e-mails and all of their attachments are scanned for viruses and other nasty tricks(!)

Email Attachments

The types of attachment to an email is an important part of the 3SL email filters. Therefore, the 3SL email filters are very sensitive to the types of files that are attached to e-mails.

We currently block everything that is remotely executable. This includes the obvious ones, such as:

  • exe files
  • scr files
  • msi files
  • .bat files
  • .cmd files
  • .lnk files
  • .com files

and many others.

We also block file types that are common vehicles for malicious code, including the obvious ones:

  • .jar files
  • .ace files

and others that we will keep to ourselves!

In total, we block over 20 file types.

Accepted Attached File Types

We want to receive your e-mails! Therefore, if you need to send any attachments with your e-mail, only send:

  • Microsoft Office files
  • Open Office files
  • PDF files
  • Plain or rich text files
  • Cradle import/export files
  • Simple images

We will detect macros in e-mail attachments. So, please don’t send us any file with a macro inside it!

If you send a file containing a macro, then either your e-mail will be rejected or, if you are in our whitelist – and this includes customers – then your e-mail may be logged as spam, or it may be rejected.

Alternatives to Email for File Exchange

If we need to exchange files with you that would be blocked by our email system, or by yours, there is an alternative!

Every login account in our website can have a file transfer area. You can use this area to download any type of file from us. You can use this area to upload any type of file to us. Therefore, this mechanism avoids any need for us, or you, to send files by e-mail that either of our mail systems would block.

We think that this mechanism is very useful. 3SL asks all of our customers to consider using this mechanism. We hope that you will agree.  Therefore:

  • If you have a login to our website, we can enable this facility for you.
  • If you do not have a login to our website, please register and create one!

Your organisation may also provide a secure file transfer mechanism. If so, tell us about it. We will be pleased to use it.

Help Us to Help You

Obviously, we never send anything malicious to anyone. Equally obviously, we do not ever knowingly send any emails that could be regarded as spam, malicious or suspicious. So we would be concerned if you do not receive any of our emails.

Therefore, please tell us if you believe that we are sending emails that are being blocked by your mail system.

If this happens, then we will work with you and your IT to either:

  • Add 3SL to your organisation’s whitelist, and therefore none of our e-mails will ever be blocked
  • Or we will change the format of our emails so they are acceptable to your organisation

Banking Changes

Changes to 3SL Bank Account Numbers

In response to the 2008 financial crisis, the UK Government has decided that all major banks must protect their personal, retail and most business banking operations from their more risky, often speculative, investment banking and international banking operations.

photos of city banks (Pexels.com)
City Banks

Most major banks in the UK will do this by  creating a new ‘ring fenced‘ banking operation that is protected from future problems in the financial markets.

Most of the UK’s major banks will effect this change in April 2018.

For 3SL, these banking changes will mean that there will be a new BIC (bank identifier code) within the IBAN (international bank account number) of all of our bank accounts. In  effect, all of the IBANs for our bank accounts will change in April 2018.

It is also possible that banking changes may effect another part of our bank account numbers, called the sort code (similar to the ATA, routing number or branch number codes in other countries’ banking systems). If there is a change to our sort code, the change is likely to occur in January 2018.

If you are an international supplier to 3SL, or one of our international customers, then it is possible that our IBANs will change in January 2018, and they will definitely change in April 2018 when the new ‘ring fenced’ bank in Barclays PLC receives its new BIC.

All of these changes are being completed in advance of the UK Government’s deadline of January 2019.

Our current IBANs will remain available for 36 months after the change in April 2018.

We apologise for the inconvenience that these changes will cause to our UK and international customers and suppliers.



6th June 2018 – Barclays have confirmed the new SWIFT BIC code is BUKBGB22. Our sort code and account numbers have stayed the same but our IBAN numbers have changed. Please contact salesdetails@threesl.com to request our IBAN numbers.

Cradle-7.2 is Available!

We are pleased to announce the release of Cradle-7.2!

3SL Customers with active maintenance have been sent an e-mail notification of this release, and details of which enhancement requests and bug reports are in it.

New Capabilities

Cradle-7.2 contains a range of new capabilities that are described in its release notes:
Some of the highlights are:

  • Full support for IPv6 networking
  • Availability of 64-bit Cradle for Linux, use of the latest Windows .NET and improved support of Office 2016
  • Locking projects and disconnecting users through Project Manager
  • Improvements in custom web UI components, and the as-supplied Basic web UI
  • Dashboards as dials in WorkBench and in web UIs
  • More flexibility with Change Tasks in the CM system
  • Extended quality checks in the Conformance Checker and for SysML in the Consistency Checker
  • Find and replace
    – Extensions to queries and views
  • New functional modelling options with PADs and IDEF0


Cradle-7.2 available from our website here:  https://www.threesl.com/downloads/software.php

You need a new Security Code for Cradle-7.2, other Security Codes cannot be used. There is a database conversion from 7.1 to 7.2. The converter which run automatically if you install Cradle-7.2 ‘over the top of, in the same directory as, the earlier version of Cradle from which you are upgrading.
You must upgrade all Cradle installations to 7.2. Cradle-7.1 clients cannot connect to a Cradle-7.2 server, and a Cradle-7.2 server cannot serve Cradle-7.1 clients.

We hope that you will welcome the new capabilities in Cradle-7.2!
Cradle Dashboards