John,
Thanks for the offer.
When you say Anthony are you refering to user Valliantxxx (sorry, I forget the number - xxx. Apologies to Anthony)? If so, the DMU you're refering to is a class 117, not the Derby Lightweight. That DMU model is from the now discontinued WSR (West Somerset Railway) payware pack, which, incidently, I have.
Anthony, Valliantxxx, I believe now owns the copyright to the WSR assets and has commissioned/asked user arrarial to improve the WSR class 117. I think with the appearance of T:ANE and all its demands on asset parameters, they've had some setbacks with the updates.
User pterodactyl is the original author of most WSR assets.
I don't have plans of the Derby Lightweight but I will try and find some if necessary.
Rob.