What an interesting thread. Old white woman here, experienced all sorts of financial situations, apart from being well off! IMO, class in the UK is about so much more than money and wealth. Behaviour, speech, education, appearance are all markers.
DH and I never earned much above the national average between us, but our main aim was to not live on the kind of council estate he grew up on, where the lack of a strong local dialect was not popular! Our DC, born in the 70s, have achieved so much more educationally and materially than us, as have their partners, neither of whom started with much. There were so many opportunities then. As working adults they have never (unlike us) had to worry about having no coal, or only beans in the cupboard for their child’s main meal.
Although we are now retired and on a fairly low income (not all baby boomers have gold plated pensions) our speech, values, tastes etc are similar to those of our DC. We live in a very ordinary small house that we own, they have large homes, one owns land, one has a second property that is rented out. Are we different class?