This happened to me at the T5B lounge a couple of months ago--at a time when I was on a layover in between a red-eye and an onward flight, and really needed a shower. I was there for over an hour and it did not get fixed--they were sending everyone to the public toilets. Oddly, there was still breakfast food being made, so there must have been water in the kitchen??

I wrote in a complaint via BA.com about it and heard precisely nothing back.