SamMobile.com have all the firmwares. Just search for n7100 or n7105 depending on which phone you have and then look for a UK ROM.
Any particular reason it has to be a UK ROM btw?
Uk MB2 (n7100) here: www.hotfile.com/dl/195915786/1eecb2a/N7100XXDMB2_N7100OXXDMB2_BTU.zip.html.
Cheers mate. No particular reason, just figured UK one would be most appropriate?

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. Quite a few people seem to have issues with them taking ages (or just sending the phone back after a factory reset/flash of latest ROM) :/.
I inspected it closely and as clear as day there is a small dent there, as well as a small scuff in the corner where paint has peeled off, something that might happen if you drop it. Obvious to say I refused to take the phone back in that condition as it is not in the same condition I brought it in to them. I am now back to square one because they had to book it in again with the repair centre to 'check the damage'. I've had enough.