Are you me? Almost identical to our situation last year. Will you have a crossover period between completion on the new house and moving in? We had a month which meant the rewire could happen very quickly before we moved in. Do not under estimate this job! Our house was not liveable during the rewire. It was much less than £7k too.
Things to be aware of:
Every wall we stripped of wallpaper needed replastering and sometimes re boarding completely. If you have any rooms with the wallpaper still firmly on, just paint over unless you want most of your budget to go on plastering.
Everything costs more and takes longer than you think.
YouTube everything. Get the right materials and you can have a go at most things.
For our budget (same as yours) I've:
Rewired inc outside lights + sockets.
Re plastered 2 bedrooms, hall, stairs, landing.
Re carpeted 2 bedrooms, hall, stairs, landing.
Painted the living room, 2 bedrooms, hall, stairs, landing.
Painted kitchen cupboards, tiles, and changed worktops.
Had a small roof repair.
Stripped internal doors and painted them.
Plastering has been the biggest cost, then rewire, then carpets.
Pm me if you want any more info 🙂