That does sound tyre related. Might sound a daft question but is it fitted correctly? I have seen one where the fitter put it on the wrong way round! And more than one where he actually damaged the wheel! And several where the wheel wasn't balanced correctly after the new tyre was fitted and the regular . . . adjusters on the rear were not set correctly. Trust the "experts" - no way!
Yes, front is fitted correctly and has been balanced multiple times by two different mechanics, just to make sure. I've ruled out balancing issues.