Thanks for the reply.No, the NHBC won't be interested as the builder is rectifying the work under their warranty.
I suggest you focus on the problems with your own house and and not try to stir up trouble with the builder by involving other home owners. If you find further problems with your house that you need resolving, you don't want to have generated the reputation as a trouble maker for yourself with the builder that you will be relying on to rectify the faults.
I have since spoken to NHBC and they very much are interested, especially as this issue affects more than one property.
I think I can safely say you have never been in this situation. It's been a constant stream of initial poor workmanship followed by a never ending drip drip of poor quality workers who come in, do a bodge job and often leave new damage. Major problems we've had are first floor flooring having to be taken up three times to 'rectify' structural issues in the sub floor which will never be fully resolved, five large holes cut in the living room ceiling to connect the radiators up properly, heating system wired wrongly so the boiler was running 24/7 and hot water only worked if you had the heating on. (we were told that we should use immersion heater for hot water as gas doesn't heat the water - a complete lie). Sewage smell coming from shower drain that they've tried to fix god knows how many times over the past year and are yet to succeed,
Having lived in the houses for a year, we mostly know each other on the road and of course discuss common issues with our houses - especially things that are not obvious to an untrained eye. That is not stirring up trouble, that's letting people know of a potential serious injury risk in their homes. You might be happy with the thought of quarter of a ton of tiles falling onto you/your children while showering but I'm not.
Ted