Look for any area of ex-council housing that was bought via right to buy where the elderly residents are, erm, moving on. I suspect we are entering the tail end of this phenomenon though.
In those areas you have houses with one occupant, possibly a bit run down / dated. They die and the new owners do it up either to live in as a family home, or to make a profit.
In my area of South West London the Dover House Estate is a good example. Quite pleasant cottagey terraced houses with lots of green. Values have doubled or even tripled in the last 10 years, and the feel of the area has got more positive (not that it was bad before).
Key things:
- Demographic historically bought under right to buy (so not too much Council Housing left).
- Those that did right to buy liked the area so stayed. So a lot of elderly owners remain.
- Few houses moved to HMOs or other BTL.
- Area is mainly houses rather than blocks of flats.
Other estates I expect to be similar. Castlenau in Barnes is probably further down the 'on the up' path (until Hammersmith Bridge broke). There is an area near Wormwood Scrubs that looks similar from the A40 that feels like it is an opportunity.
Wikipedia has a list of the cottage estates: en.wikipedia.org/wiki/London_County_Council_cottage_estate
The same applies for areas of 1950s council housing too.
I dislike 60s and 70s council housing, it is usually flats rather than houses and doesn't seem to have lasted well due to poor designs. So the approach is often to flatten and start again (e.g. Elephant and Castle, Roehampton Alton Estate). So buying in those areas is a gamble on the compulsory purchase price being worthwhile to move up. In the interim the area gets worse.