If you do end up sending the tyre off back to Metz, and worried that they could deny anything about it, if it was me as well as taking close up pics, I'd also be taking a photo of the tyre with your Reg plate number in the frame if you can, even if you have to unbolt it to hold it near the tyre when taking the photo.
That way if you do end up having to take legal/other action and need to prove that you had the tyre you can. And if they want the original invoice, make sure you scan/photocopy that to! As I've had companies in the past saying they've not received/lost it and without the invoice your screwed for proof you've bought it.
Had Similar hassles with bridgestone a few years back, denies there was anything wrong with their tyre that had clearly overheated and shredded in 400 miles... wouldnt have minded cept it werent a super sticky, jus common road tyre..... Anyway, point is... There is no reason for you to deal with metz/pirelli yourself. Under UK law the shop that sold you the tyre should be sorting it and if they cant prove theres nothing wrong with it then they should be replacing it or refunding you the money. On a different note.... Look up Fred Furlong on facebook (Furlong Tyres), he only does bike tyres and been doin it for years, show him the pics etc and he may shed some light on the matter or at least be able to help you out. Fred caters for drag/sprint/circuit racers the lot..... So he's def seen a stressed tyre or two in his life
Thanks for that pal. I will look Fred up as you suggest but as for my tyre dealer he's still not replying to my nail so next step is a final email to him followed by trading standards and see where I stand on this matter. Thanks.