Only joining the EEC had little, if anything, to do with the recovery and change of coffee.
You remember a country still suffering from WWII and loss of world leader role (and colonies), in a much poorer global period. For starters, the '70s had a global recession and oil crisis, and many countries were affected, not just England. Have a look at pictures of New York of the same period -- it looks like a third world country [1].
In the 80s and 90s, countries that didn't join the EEC, as well as countries that joined EU much later, had the same economic uplift.
(And of course several countries that did join the ECC/EU had economic decline and crashes, e.g. the P.I.I.G.S).
Yeah there were many factors. The UK used to be quite socialist in the 1945-1975 period which was OK for the NHS but many other things like British Leyland didn't work so well.
You remember a country still suffering from WWII and loss of world leader role (and colonies), in a much poorer global period. For starters, the '70s had a global recession and oil crisis, and many countries were affected, not just England. Have a look at pictures of New York of the same period -- it looks like a third world country [1].
In the 80s and 90s, countries that didn't join the EEC, as well as countries that joined EU much later, had the same economic uplift.
(And of course several countries that did join the ECC/EU had economic decline and crashes, e.g. the P.I.I.G.S).
[1] https://allthatsinteresting.com/1970s-new-york-photos#8