Looking at converting understairs cupboard into a downstairs loo. Neighbours had this done many years ago so I know it’s doable. I’m looking at one of those toilets with a built in sink in the cistern to save space (I’m disabled and don’t want to be negotiating a sink sticking out of the wall every time I use the loo), so just wondering if I need hot water to the sink for building regs? Can’t find anything on the gov website about this. Will install one of those little water heaters if so. Thanks :)