For ordinary people, it was harder to get a mortgage then than in the late 80s/early 90s. Until Mrs Thatcher deregulated mortgages, they mostly came from buildingsocieties, very few from banks. Building societies were mutual organisations owned by their members, who were the savers and borrowers. They didn't make a profit. They required borrowers to save with them for a year or two to build up the deposit, which had to be something like 5% or 10%. The amount you could borrow was a multiple of your earnings - 3 times, typically, for a single person, or 2.5 times joint income for a couple (or 3 x the higher income and a smaller multiple of the lower income).
I'd imagine, though, that the Arthur Daley types who were making money would have had ways round all that. Plenty of ways to make money with all the nationalised industries being sold off, too - shares were marketed to the general public. British Gas, British Telecom are the ones I remember.
Council houses too, of course. Sitting tenants were able to buy them at a huge discount and after a certain time (two years?) could sell them for market value and pocket the difference. (No replacement council houses built, of course.)
Then she came for the building societies. When mortgages were deregulated most building societies ended up being bought up by banks (or vice versa). Bonanza time for the members, who became shareholders, and for the directors, whose salaries rocketed (share options too). Dreadful consequences for the housing market, though, as we are seeing all too clearly now.
There was a big crash in house prices in 1989 which lasted for several years. It followed the abolition of tax relief on mortgage interest for unmarried couples and then later altogether. Lots of people were in negative equity for years in London.