Give these guys a call or email - I believe them to be the outfit Adrian dealt with very successfully a couple of years ago and at a very reasonable price. They are about 50 miles away from me.
http://www.stainlesssteelexhausts.co.uk/They seem the sort of outfit you could send yours down to as a pattern and will make you one up as per.
They have just fitted a Morgan V6, 3.7 with a brand new lightweight stainless steel sports exhaust - so they know Morgans.
