Im obviously confused. Lol. You said you were leaving Thailand for 4 days to get a visa. Thought it was imminent. And if 4 days was long enough for visa to be issued.
They will wonder why you are border bouncing with visa exempt so many times, which suggests you're trying to live in Thailand without getting a proper visa.
Hopefully like other countries that use this type of form, your airline will ask you to confirm you've applied. The UK govt website has up to date info on entry options/requirements.