Class is bunkum and these questionnaires and catagorising labels are utterly subjective and their flaws have been pointed out by several OPs. These class classifications are as beguiling as horoscopes and just as meritricious.
Wealth is wealth, a measure of income and capital. The more money you have the more power it buys you, break the law and it buys you the best (and most expensive) legal advice, give it away to charity or political parties and it gives you power over the recipients. It buys your children a good education and they have a headstart in the race of life. That power can be used to serve your best interests, regardless of their affect on other people. What money can buy, when money is no issue can be used for good and ill and, to be fair. many wealthy people do put their money to good and charitable uses.
A lot is made of our 'upper class' Eton/Oxford elite who govern this country, but behind all that is the money and wealth that paid for it. They went to Eton and Oxford and they now govern us because their parents were rich, not because they were 'upper class'.
Reverse the above for the effect of having little or no money, for the poor life is a struggle, get into trouble and you will be lucky to even get legal aid to defend yourself, you are likely to be badly housed, your children are more likely to be at the worst schools, live in the worst areas, have the worst health.
Schooling, housing, work and access to the best of services are the factors that dertermine peoples lives, not some silly subjective questionnaire that plays to the hopes of those who complete it.