Can a non-UK citizen apply for a DTV at the Thai Embassy in the UK?

Hey, has anyone applied for a DTV via the UK Thai Embassy as a non-UK citizen/resident and been approved? I already have a DTV but my girlfriend (from South Korea) is visiting the UK with me now, and I wasn't sure if she'd be able to apply for a DTV here instead of doing it in Vietnam like the majority of people do.

I had heard that some people applying in Western countries were being denied if they were not from that respective country? Any insights or experiences people have with the UK Thai Embassy for their DTV application as a non-UK citizen would be appreciated.

Thanks.