One major restriction has to be a covenant that you can only ever buy one of these if you meet the means-test they were initially sold under. That limits the ma

One major restriction has to be a covenant that you can only ever buy one of these if you meet the means-test they were initially sold under. That limits the market and the mortgages available therefore caps the price. That or generational (eg 35y) leaseholds. In the UK apartments are almost always leasehold anyway, but a long-but-not-too-long lease would mean it always returns to the state without being resold or sublet indefinitely. I agree, defining "means" in a means-tested transaction can be tricky but also, it's just data. If you can't or won't show enough history (even homelessness leaves a trail), it's not hard to find someone else who meets the criteria with a better history.