For 1 year marriage extension are immigration fussy about where the funds are from or just interested in how long they've been sitting there? Both me and the wife have funds already in Thai bank accounts. With the rediculous uk exchange rate I don't really want to transfer from the UK.

Proof of 400k baht in the bank for 2 months by way of a letter from your bank and your bank book.or 40k baht income.proven by a income letter from your embassy.

 

No need to prove where the money came from. 

Maybe dependant on the office, Its usually just 400k in an account 2 months prior BUT it needs to be in your name, not a joint account with thai wife etc. 

Yep. Your Wife's finances have nothing to do with it.

There is no requirement to prove the funds came from abroad when using the money in the bank option when applying for an extension of stay.

Thank you chaps for the quick response. After the extension is granted that money can be moved or needs to remain static? 

29 minutes ago, Jimmy B said:

After the extension is granted that money can be moved or needs to remain static? 

After the extension is stamped in your passport you can do whatever you want to with it.