I used Siam Legal on Sukhumvit for translation of Affidavits from UK Embassy. They also handled the legalisation with the MFA. Might not be the cheapest but I got a really good service.
, as I said in response to Andy above, I had to pay 11,000 THB. I wasn’t offered anything for 7,000 THB. How long did it take to get the passport back?
We were told 10-12 weeks wait when we submitted the application on 9th May. Decided to pay for the express processing (approx 3000 THB I think) and it still took 3 weeks.