I used this guy:
Steve Harris Unit 6, Bridge Ind Est, Silfield Rd, Wymondham
Norfolk NR18 9AY 01953 601954
to make me new stainless steel exhaust pipes for my '40. He was really cheap and the work is excellent. He is ex-Lotus and will make just about anything you want in alloy or stainless including header tanks, swirl pots etc.