Empty of all furniture, it would be around £3,000, Derek.
In the real world, with it being inhabited, it does add a lot to the labour cost. Referred to in the business as "house-bashing", you'd be surprised at how many electricians try to avoid this sort of work. It's a real chore. That would put the cost up to around £4,000.
Quite often, it's impossible to pull cable through existing channels. Chasing in would be needed. Then there's plastering and re-decorating. That would be another cost.