At a quick guess I would say there were around 80,000 undated 20p coins that entered circulation
They were NOT withdrawn from circulation by the royal mint but by people who found them in their pockets, putting them on ebay .
How do you think the royal mint would withdraw them anyway? The only way would be to get banks to take them out of circulation and as there are about 20 000 000,000 of them in circulation it would cost a fortune to sort every mint bag in every bank , it would also have to be done on an arranged day , the man hours involved would be massive
Do you seriously think the royal mint would do this - no chance - they even said in a press statement that they were "worth face value" no more.(folks on ebay thought differently)
My brother worked for a bank at the time and he never heard of this recall.