You could convert a Deac SMLE into a Deac carbine and have it re-proofed as a deac, that way all parts get the stamp and a new cert with .45 and new barrel length printed on it. If I had access to the parts (And equipment), I'd have a go, it would prove to expensive for me to buy a deac SMLE, Thompson, Lanchester Mk1 etc. to make a deac delisle. I do know of a very expensive UKicon made replica, a very very good one made off the plans, (there are live versions available also) deactivated £2500.