Hmm. Seems the cheapest option is buying a new panel - £275.22 + VAT from Triumph
Plus £30 for the top decal. They don't do spares for the Masterbike decals so I'm having a graphics shop imitate them for me.
I have a few spares, all scratched (bought that way I would add!!!) and I'll shove the lot on ebay soon.
Plus, the tail piece - I bought a new one on ebay for £47, not worth repairing the original, so also going on the bay shortly.