Clive, thats good work you do. There is another chap, I am not too sure if he is here, his name is Paul, also in the UK, who uses CAD for lithograph work for model trains. I will send you a PM with his contact details as I am sure you two could have a good ol' chin wag.
As for CAD, I too am formally trained in AutoCAD and SoildWorks and like both, but I have BETA tested DesignCAD since the early/mid 90's, BETA test DoubleCAD and have been involved with DoubleCAD since it was first started and even had a name. I am also involved with TurboCAD Pro and like it and with TurboCAD LTE - vanilla and Pro versions. DoubleCAD and TurboCAD LTE and damn near identical except for a name - I think it is a marketing tool for IMSISoft and a very well market exercise that seems to work for them.
The reason I started this post was to gauge who was doing what with this program so I could get a direction or two or three as to where to go with creating more tutorials. I have created one already for TurboCAD LTE a modified verison of the DoubleCAD one - a basic lets learn CAD thing and now working on an architectual tutorial. The first tutorial is now for sale on the IMSI website, as will all tutorials I do. I have a number in mind all updated from my work with DesignCAD.
In all, I find DoubleCAD/TurboCAD LTE and LTE Pro very good little (not so really) programs and give AutoCAD a good shack round the neck! For many users, these programs would be MORE than ample for the end product and I do not know why people go to AutoCAD when there is this stuff out there. Marketing, as they DO NOT know it is there.