Not sure what sort of licences were issued after I got mine. They changed the rules in the early 70's, before that you had to renew every 3 years (before that, you got a little book, still got mine ). When mine expired in 1975, I was issued with a licence till 2019, might sound good but 3 year licences cost £1, they upped them to £5 for a 70th birthday licence.
A minority still use the traditional all-paper licences, which are no longer issued. These are generally valid until the holder’s 70th birthday, as long as personal details are still correct.
Pete