I am in the process of trying to replace a lost UK passport.
I emailed VFS (HMPO) about the need to visit their Trendy office twice in Bangkok, to deliver the application and then subsequently collect the new passport,
In my case this would have involved 2 x 14 days self isolation on returning to my home in Phetchabun. This is their response :- "For applying renewal passport you may come to apply application by yourselves, by your family/relative/friend or use representative to submit application on your behalf."
It's as if they've never heard of Covid19/quarantine etc or maybe it's the case that all their staff have been vaccinated, so why should they worry about lesser mortals from the outlying provinces?
I have decided to use an agent, to cut out the hassle. Hopefully it'll be 5,000bht well spent.