I had a shared-ownership flat for a few years until recently on a mixed-tenure estate in London.
The estate was made of a tower with luxury flats sold on the open market, a couple of buildings with shared-ownership flats, affordable housing aimed at key workers, and one building that was used to provide social housing to tenants found by a housing association that managed the estate.
I must say that the shared-ownership buildings were the ones that were always tidy and quiet and housed really nice neighbours. ''Affordable'' housing like this in London is actually still quite expensive as you pay a hefty service charge, ground rent and rent to a housing association on the share you don't owe so the people who buy these properties are perfectly decent people with normal jobs.
The problems we had were always with with the people living in the luxury flats or the social housing tenants.
Many of the luxury flats ended up as buy to let for investors and we had tenants smoking cannabis in there and a prostitute using her flat to see clients...
All the noise nuisance we ever had always came from the social housing tenants (loud music for example).
So my point is if the affordable housing on the estate you are looking at is shared-ownership or Right To Buy, you are likely to get couples, individuals or families who just happen to be first time buyers that can benefit from government schemes or people who are teachers, nurses and so on and have slightly lower income. There really is no issue with that in my experience.
If I am completely honest I would not buy again on an estate that has housing reserved for social tenants though (people who are council/housing association tenants), because although again most of them might make great neighbours, the experience I had was there is also a strong possibility of having ''problem'' families or individuals being housed and then the housing association does very little to address anti-social behaviour. We also had a council estate nearby and again although most tenants were great, we had a couple of dodgy ones that ruined it for everyone else: loud music and gang activities.
I know it is not fair to think of social housing tenants in this way but when you have lived through some of these issues it makes you rather wary so I know the OP is being criticised but frankly I don't blame her for being cautious and investigating things further.