It was extremely common to find florins and shillings in change though it gradually lessened up to 1990/2 when the sizes changed and they were all withdrawn. It was also possible to find pre-47 silver, usually George VI. The humble sixpence also survived until 1980, though there never was a 2 1/2p coin.
Note that the mintage of 10 pences and 5 pences (from 1968) never came anywhere near the mintage of 1971 bronze, for precisely this reason, that florins and shillings were only gradually withdrawn.
copper123 - you didn't see ANY copper after August 1971 as it was no longer legal tender. In fact halfpennies were demonetised in 1969, so only pennies survived to 1971.