'Medical' masks just means standard surgical masks, not FFP2/3 masks (for the differences, see
this article)
I went to Germany recently and most people were wearing standard masks. My vaccination certificate and locator form were checked before departure and after arriving in Germany.
I came back into Heathrow and found very short queues and the e-gate let me through without a manual check of the forms being required, so I was able to get the HEX train 75 minutes earlier than the one I had earmarked as the latest to get my onward connection.