British standards are all BS. The electrical wiring one is BS7671. It divides the bathroom into zones: https://flameport.com/wiring_regulations/BS7671_selected_sub...

Zone 0 is inside the bathtub. Damn, so I can't put an outlet there? Zone 1 is over it, and zone 2 is 2 feet around it, and allows 12-volt outlets for small gadgets. Beyond that you can have ordinary outlets with the right circuit breakers (aka RCDs, GFCIs) integrated into them.