Two of my colleagues did this recently with there being no fuss on arrival into LHR, after showing their ID to immigration. Both were not wearing uniform. It would seem that the biggest challenge was dealing with ground staff prior to departure, that perhaps don't know the rules. It may help to print and carry the legislation from gov.uk.
There are rules for performing Lateral Flow Tests after you arrive in some situations but I can't remember who it applies to. Have a careful read of the rules before you go.
Edited to add that both colleagues were travelling from a red country.
Last edited by Mister Geezer; 7th Jun 2021 at 12:03.