I have had lots of great advice here about areas of East/SE London before, but I'm afraid there's now a new twist in our increasingly baroque househunt. 
If we decided we wanted to live somewhere more central (I mean like Bethnal Green, Rotherhithe kind of distance out) we'd probably have to go for an ex-local authority flat in a low-rise block to get the size place we'd want.
I wouldn't think twice about buying an ex-local house freehold but are flats a bit different? I know the freeholder will be the council/housing association and there are horror stories about being stuck with huge bills when they do works on the building. Also there are ground rent/service charges etc as with all flats, and that leases will generally be under 125 years.
Anything else I should be aware of?