In the 70s the UK air pilot stated min 1000ft per min except for the last 1000ft unless exemption given by ATC.
Mode C wasn't available to all, was unreliable and consequently when stacked going into Heathrow we were expected to maintain min descent rates and often called "vacating Fl..."
In those days we could have an hour plus holding.
I've held over red fir south - then clacton b4 going into the ongar hold.
likewise over Ram Bullet a couple of times.
Boredom was filled with The Times crossword, some tasty hostesses and bull s***ting interesting first class passengers - all gone now.............
Lucky to see a clean hostess nowadays................