In Europe it's quite common to put the washing machine in the bathroom. For that you need socket(s) and it's normal there to have them. I mean, you don't have your wash-basket in your kitchen right? In the UK we have to make regulations about every little thing because we are a nation of busy-body wool-wrapping nanny-state bureaucrats. If we're not regulating something we're complaining about others having more fun or being louder than us and wondering whether there's a regulation for it, and if so, are they breaking it? It won't be long before one has to legally wear a hi-vis vest to leave one's house.
I think your allowed a socket 300mm from a sink bowl so most of those are ok. The issue is a bit more difficult in a bathroom as it’s got to be 3m from a bath or shower but if you have a fixed shower screen it can be closer
Well why wouldn’t you if your capable. Nothing against it personally! Loads of on line resources and the chances are it probably won’t seriously harm anyone!
The regs say you have to be a 'competent person' whatever that means. What gets me, is every time I visit a place, even new builds, I see stuff not done according to the regs. Somebody signed off on this... I believe that's what causes disasters like Grenfell at the end of the day. Someone signs things off they shouldn't.
I put them in to stop the critters snakes and toilet fish getting in… or really because the traps evaporate and stink the place out