I am a Proto class representative so if you have any questions feel free to email me stevedickens@hotmail.co.uk. what kind of chassis you looking for? I know where there are a few! As for the gearbox we opened the regulations up a few years ago so proto can have up to 6 forward gears and one reverse in H pattern or sequential.
Welcome Sean, I am the Chairman of the Clubmans Register (until our AGM on March 12th at least) and look forward to meeting you. I'm quite sure you will all the info' you need via your posting, but please feel free to contact me (email link at foot of message) if you have any unanswered queries. Best wishes. Chris.