We recently had a new bathroom fitted, and had bought all the bits ourselves, with the fitter (next door!) doing all the real work. Anyway, one of the taps handles on the very expensive (£126) tap unit on the bath kept working loose, and repeated tightening later eventually stripped the thread of the grub screw hole. So, I phoned up the people who we bought it from, explained what had happened and could we have a new handle please. A couple of days later a COMPLETE tap unit arrived FOC. Yes, the whole £126 worth.
Thanks Victoria Plumb, that's excellent customer service.