I'm sure this has been done before on here and I'm sure a few members have some recent experience so I might as well ask…

I've been offered the chance to buy a 1950's 3 bed semi in a London Suburb at a very good price (for London).

The bad part is it would need new;

Kitchen,
wiring,
Bathroom,
Heating,
Windows,
carpets/flooring,
plastering & decorating throughout,
garden clearing and sorting.

What's the collective rough estimate? Would a total of £25k inc labour sound about right? The assumption is the exterior walls and roof are sound and there will be no structural alterations.

doing up to live in? or to sell on?

i gutted and re-did a 6 bed farmhouse for £27k, but did a lot of it myself and used tradesman doing labour only on foreigners – ie evenings and weekends for cash

depends on how much time you have and how good you are at practical things?

It'd be to live in for probably 5 years or so.

I'm working full time so will only do the simple stuff, and having had a go at plastering & basic plumbing a few years back know good tradesmen are worth paying for.

and used tradesman doing labour only on foreigners – ie evenings and weekends for cash

seeing as it's semi detached just bear in mind the noise regulations of your local council.
I had my upstairs neighbours doing the place up on the cheap with a succession of tradesmen at all hours up to 11pm and doing silly things like using an angle grinder in the garden at 9pm on a sunday (small garden with a dozen houses backing on to it)
got the council involved resulting in them having a written warning and a couple of visits.
tradesmen working out of hours is illegal unless it's an emergency.

Should be possible, up north you'd get a good standard for that. A lot of guys are really struggling for work at the moment and will work for a big cut. However these are usually the ones that have to advertise and don't work off recommendations, can be more miss than hit.

If you want any advice for diy bits, email me. If you're a practical type, you'd be surprised what you an achieve.