Lol. I got it from Thai consulate in Hull, UK. Very possible. They even have triple entries before. Please double check if you think it's impossible. I can even attached my old visas and stamps if you want.
I can't remember 3 or 6 months bank statements. I used the Barclays statements. Dependant visa is easy to get if the girl is your wife (not a girlfriend).Can't remember the visa type.
She is allowed to work full time on dependant visa. After that she can apply PR in UK. Everything is easy straight forward in UK. Just ask the requirements at the British embassy in Thailand. Good luck :-).