"in principle, people who are working should not take housing association properties - they are there to subsidise the needy, not those who just like to have more of their income to spend on themselves. but that is a principle."
That is absolutely untrue.
HA/Council houses are allocated according to need. One of those factors is the ability to house onself in private rental/bought housing, but there are many, many more factors.
We live in a Council house. We are very, very, lucky. I had been told it would be 5/10 years before we could expect a house the size/type we needed to come up in the location we needed.
We were initially put in band 3 on the housing register (which is the band that pretty much everyone gets put in) but then got uprated to band 2 because of DD1's disability.
We weren't uprated because we have a low income (although we do, DH earns just over £10k per year). We were uprated because the private rental we were in was unsuitable, and the space we needed was hard to come by, and other things.
When the bidding came through for this house, we finished 3rd. But the council still contacted us, I don't know why.