Going back to the mains electrical sockets, getting them at 450mm or above would not be a problem if mounted on the side wall of a kitchen base unit, just leave the door off that one. But with the prospect of selling the property you should be guided by youur electrician and in a compliant location. The stupid thing on socket positioning is that you can drape a flexible extension socket block anywhere it's convenient, though preferably not where you will trip over it.
On layout wiring, as I've now got to an age where high mounted sockets are a godsend, putting point motors, relays and the other layout wiring where they are accessible from the front is well worthwhile if practically possible.