Same experience for me. I was amazed with my Christmas Day surprise from the Thai Embassy London. TR 60 day single entry visa approved within 3 days of application.
I used this company last year and for my current stay. Efficient sign-up and policy dox sent immediately by email after payment. No problem with using for visa, ThaiPass.
It does seem to be something of a lottery. I applied for mine from U.K. last Thursday and Sandbox approval was provided Monday, so was 2 business days.
I provided cropped QR codes from my NHS Covid Pass and I’ve also taken out Thai insurance cover from Luma. It seems that this has definitely helped to make for a quick approval.
Did my PCR test at Boots yesterday and got the result this morning so I’m now looking forward to my Etihad flight to Phuket leaving LHR on Friday lunchtime (fog permitting!)
I went to Thailand in March when the U.K. was in lockdown and have just returned as Thailand is currently in lockdown. I’ll return there in New Year and recommend you do same.