Not really an in-game thing but thought it was probably best under suggestions. I think a definitive support article with a list of what is and isn't compatible with the Livery Designer would be really useful, and save us the pain of trying to work out which Mk1s work and which don't etc.
I’m disappointed that some of the older locos aren’t on Livery Designer. 31’s and 33’s would be amazing with something other than BR Blue and Br Green.