Heathrow T2, not too busy but very slow.
PRINT the required documents, the amount of people who didn't and then had to pay an over inflated fee at a nearby printer was unbelievable.
Documents requested:
1. Passport
2. RT-PCR certificate
3. Thailand Pass
4. Visa if required
Check in said the flight was full, but I have no idea. "Leg room seats" now come with an £80 additional charge (the ones by the exits - I've not be charged before, could be a misunderstanding).
ATM cost £2:50 to use once through security so get your GBP before hand.
Most eateries are open.