Yep the can (silencer in Old English) is a Fishtail and it sounds like nothing else. Melifluous is the word I think!
I'm currently running it on a Brooklands can - louder and more top end. I've also tried a straight through pipe, which gives better bottom end but not so much a peak revs. (Tuning this stuff is easy and rewarding cus there is so little power in the first place!).
I have another engine/gearbox and I'd love to put it into something like a 250 TZR frame............... the DVLA

would probably want to arrest me if i tried to register that
Perhaps a VTR 250 frame would do the job??
She's my idea of beauty and thats what I ride.