An embassy or consulate will accept a marriage certificate from a foreign country if it is in English or if you have a translation of it to Thai.

You have to go to your embassy if your from the UK to get an affirmation of marital status once done you need to take it and your divorce papers and a copy of your passport to a translator who will then translate it. It cost me 500baht. Then you need to take all this to the main government offices in Bangkok. To get them stamped. Ho you must state where you will get married and in what month you will marry in your affirmation. I done this a few weeks ago a lot of red tape and running around!!!!