so when you get there you go through their immigration and process their visa upon arrival and exit the airport.
Then can you reenter the airport and process to board a flight back to Bangkok, when you arrive in Bangkok go through immigration and receive your 90 day entry???
Or must we spend the night in Laos and return the next day?
Our flight came in at 23:35 and by the time we got to immigration it was already after midnight so we were stamped in for the next day. If you have a round trip ticket I don’t believe you will have a problem. I once did the same as you and was told not to worry it happens all the time. It’s not like you are staying 10 or 20 days over, it was a simple error and the Thais understand. It will cost 500 baht per day. Relax and enjoy 😊
That’s what you want and the Thais want you to enjoy as well.
If you are from the US I think you get 30 days on your passport and then can extend for 30 days; however, I don’t know if that is the same for UK citizens???