> There's a few companies selling Japanese bidet seats in the UK

Do you have one? Are you able to make any recommendations? I'm considering getting one, but how are they powered? The idea of a power socket in my bathroom is slightly horrifying.

We decided not to in the end.

Power is easy. Only sockets allowed in bathrooms are low voltage shaver sockets with isolating transformer.

For storage heaters, these seats, and heated towel rails in your bathroom you connect to a fixed, fused, double pole switch, spur outlet. Something like this: https://www.screwfix.com/p/mk-13a-dp-switched-fused-connecti...