Bobbi Samui no, they are required to check at the uk checkin that you have a visa (or are exempt) for the length of your stay

As above. At uk check in desk they will want to see a visa for 33 days in thailand before they will let you fly. A ticket to cambodia mid vacation wont be enough as you may not use it. Id call your airline to save trouble at checkin or get a 60 day visa inline. Very easy to do

@James *******

is that in cash or evidence of in bank account ?

I think technically you should have a min of 10k thb. I have never done this when flying from the uk but do do it when i do a visa run. To be fair, in 12 years ive never once been asked for it

@Sofia ********

yes you can do that as well but max size is only 0.5mb which isnt much

Hi Steve. Residency is fine if you are uk passport holder. Just put a copy of your passport page in that section too. You can only upload one page so when you send your passport to be stamped with the visa (or visit embassy in person) put all relevant docs with it also like bank statements etc. I spoke to london embassy yesterday about this so know. Speak to them with problems as very helpful and good english