It's a Simmi Performace stainless steel end can.
Handmade in the North of England apparently, so must be good! It does appear to be very nicely made.
Comes with a removable baffle too which might be handy for the IVA noise test
Here's the ebay listing:
http://www.ebay.co.uk/itm/250800426533?ssPageName=STRK:MEWNX:IT&_trksid=p398 4.m1439.l2649
Still a fair way off the first test drive yet! Hopefully get time to drop the propshaft off for shortening this week, which'll get me one step closer.