I certainly remember going to the bank with passport and cheque book to get Deutsche Marks around 1975 on my first solo trip to Europe.
On the matter of returning to the UK. My South African friend who had scraped out under the closing gate before Christmas, got back in last week! Now doing her two weeks isolation although she will be working from home during that.
Having filled in the form online for Lufthansa, for the transit at FRA, on arrival at CPT the airport wanted their OWN form to be filled in as well. She had already filled in the online forms for the UK and printed them just in case. On arrival at LHR T2, she was asked if she had filled in the forms. When she said, "Yes" they did not want to see them. She supposes that their thinking was - she would not have got that far without having filled in the forms and having the test.
Who knows?!!