Yes you need your divorce papers . I am doing the same thing right now . I have an appointment at uk embassy and need to go and get translated which takes time and they then post the translated documents which are also stamped by the mfi to your address in thailand
Look around . You can build a buetiful house for less than 1 million baht . Unless you marry her or have your name on the tilte deeds as far I know you are not protected in any way