Had a bit of a sweat on checking in at Air France this morning for UK at Suvarnabhumi airport, I had all the correct information but I was asked if I had a recent test for COVID apart from the two when I arrived in December.
After looking through my documents numerous times, a supervisor told the lady at check in two vaccinations was enough, it was in Thai but that is what I interpreted when she put two fingers up.
TLDR : Answer Summary
Traveling from Thailand to the UK, vaccinated travelers are not required to present a COVID-19 test prior to boarding if they are double vaccinated. However, entry requirements can vary based on the traveler's vaccination status and the country of origin. The situation seems fluid; although all COVID-19 restrictions in the UK were reportedly lifted, it's essential for travelers to verify specific regulations. In contrast, entry into Australia still requires a negative COVID-19 test prior to boarding.