I live in Crescent House and didn't receive one of these letters. I did receive one about the water supply being interupted.
I didn't know they cared so much, I think they would be better of spending time measuring the freezing temperatures inside the flats.
You must be one of the people missed when the main checks were done around a year or so ago. They need to check the temperature of the water coming from the storage tanks to the cold supply in the bathroom - this is to ensure that it is outside the range that bacteria can breed in. The fact that people haven't heard of such checks before is probably a reflection on poor Health & Safety practice in the U.K.
I thought it would have been done in the summer when the temperature is more likely to be warmer enabling the growth of bacteria, above 20°C, not in the freezing weather, my bathroom water feed is so cold condensation forms on the toilet cistern and drips on the floor.
You've probably got a mains supply to the bathroom then Nathan not a stored supply - quite a few flats on GLE have which is unusual for the U.K. They probably need to check Sarah's hot water supply from her hot water tank.
Cant remember the last time I checked I should have labeled all the stopcocks, lol, think there are about four and at least one is obsolete, loads of old obsolete plumbing left in situ.I use an electric shower for washing and a kettle for everything else, the gas hot water is too expensive and wasteful, and the water tank is rusted anyway, comes out like tea, not good for psoriasis.