если летите в Лондон, то карантин и туда, и обратно 2+2 недели?

UK: "You do not need to self-isolate if you’re travelling from an exempt country and have been in an exempt country for the last 14 days. Exempt countries include all parts of the UK, the Republic of Ireland, the Channel Islands and the Isle of Man. " А вот обратно надо в Ирландии изолироваться.