The flat: is from the 30s, brick. It was built quite well I think, originally. When we bought it it had been squatted, and prior to that... god knows, but nobody had looked after it properly for a good while. It. Was. Minging.
The electrics: are OLD. Very old.
We've had a bunch of sparks through, and had three of five tell us that providing it passes tests, they can do the things that DO need doing (new consumer unit) and things we want (more sockets and some bathroom stuff) but a full re-wire may not be necessary.
Needless to say this will be cheaper. Much cheaper. They can certify it, but not for a great length - they say they'd mark it as needing testing every year. But they have said that the wiring we have could last another good length of time, and the certification is more about their regulations than doubt about the wiring.
We had budgeted for a full re-wire. But obviously saving extra £1000+ not doing the re-wire would be very nice.
I'm leaning towards doing it all - saves doing it later, we intended it do it, we can afford to do it.
But do we need to? Is this something that would add significant value if we decide to sell? Is there a genuine risk in not doing it?