Well, my local exhaust place said they do not normally fit customer's own exhausts, but would take a look for me and fit one if I could get it. The favour would cost me £70 £80 though, plus the price of the Y pipe, wherever I get it from.
They did say that their suppliers were asking silly money (£300-£500+) for their Y pipes - that's why they offered to fit my own.
I've decided to bin that idea.
I now have my Zed booked in at a place that can fabricate exhausts, so they'll make one (hopefully) for me on Saturday morning. If I can get one made and fitted for sub £200, I'll be okay with that.
Quick question, are the flexi pipes totally necessary? Has anyone (especially you guys that have had Y pipes made) got a Y pipe that does not feature the flexi sections?