I recently did a bathroom refurb', which had a cupboard within it, containing the hot water cylinder & new power shower pump etc, and was within 3 metres etc. The power shower needed a new supply, I provided a new FCU.
However, lets go crazy, and say the manufacturer of the shower pump said don't cut off my plug top. I would of installed a socket outlet in that cupboard. Making that risk assessment, as the customer will have only used the socket for the power shower and I would explain why not to use it for anything else. Would the customer unplug their power shower to plug in a hoover? If at a later date, a new owner used it to plug in a toaster, well more fool them. As I said before, I wouldn't install a socket in a bathroom, even outside of 3 meters, 'cos my customer wanted to plug in his hairdryer.
The regs are there for guidance, they can't account for ever eventuality. A mediocre modicum (sorry Sparksburntout done it again) amount of common sense needs to be applied , surely?