@Matty *******
yes i leave phuket tomorrow.
i heard all these horror stories as well and just got to the stage of " bugger it" see what happens.
it really was not an issue..both the airline and immigration had no problem with the nhs certificate and my positive test.
when i got there i gave the lady at the test centre a copy and she took details so if my day 1 test was positive it would be on record that id recovered.
also at hotel they did same..lady at hotel told me thered be no problem unless i had a very bad fever .
ironically i tested negative in thailand!!
but i felt confident i would be ok if positive.
it makes you wonder why you even need tests if youre recovered! anyway, the link to follow is latest thai govt guidance..last para makes it clear.
hope this helps!