Thanks Dennis, I might give them a ring.
Brian, I would have thought a company making these things all the time, would have some idea as to the size for nameplates for a 3.5in gauge Britannia if I told them which plates I want. All I want to know at this stage is (a) can they do them and (b) a ball park figure. I'll get in touch with them and see if they can help.
Thanks for your help anyway. I'm a bit surprised that no one on this forum has built the 3.5in Brit. I've had no responses so far on another thread. Would like to chat with someone who has completed this model.