Ah Ha! I may have found the culprit.
Checking the rear tyre again this morning I found a fluctuating run-out on the drive side tyre shoulder....just where the sidewall meets the tread.......
Rode back to the shop and harangued them politely.( Hey, I'm British).
BUT...though they agree the run-out is there they tell me the tyre needs to be sent back to Metzler for them to decide if I have a warranty claim. Could take weeks. Meanwhile I either leave the bike with the shop or put a new tyre on it and hope the factory cough up.
Reluctantly asked them to order me up another 888 but I'm not sure now whether I just shouldn't cut my losses, try to find another 880 and fit it myself.
But, hey, it's progress of a sort.
Meantime I'll check UK consumer legislation to see if, as I suspect, I have a claim against the shop as a supplier rather than against the maker.
