agreed the problem is the luggage. It will come out on the arrivals carousel. If there is a way to pass back into intl departures with the bags. If it where carryon it would be a different story.

You’ll get a 30day visa at Thai immigration collect your bags. Then being in Thai at passenger pick up. Then you’ll need to navigate the airport just like Any passenger departing. Intl departure check in, and up stairs to security, immigration. They might raise a brow here but since your leaving just stamp your exit from Thai. When you get to Cambodia they required me a US citizen to have a visa stamp. At entry double check your U.K. requirements. After your stay in Cambodia you’ll return to BKK and get a new 30 day upon arrival visa stamp. Have your past and forward travel proof to explain the quick in out of Thai to Cambodia and Thai immigration.

I went from Thai to Cambodia only staying in Cambodia the day a few hours. (Drove to boarder then walked across for the day. ) The return to Thai they held me for three hours trying to understand why I was only there a short time. Was I carrying something back? For me it was just a way to quickly visit ‘another’ country.

This would be a continuous flight to Cambodia and you’ll go through international departures. Unless you’ve purchased to separate trips. First into Thai then BKK to Cambodia.