I take it you're filling out the settlement application online(Visa4UK) for her? For the appointment in Bangkok, you need to book and pay for it at the end of the online application. Once you have a date confirmed, all your wife needs to take is her passport, the 'application form confirmation', the 'application form' itself and her A1(minimum) certificate. I was told to take the IOM TB test cert but that wasn't needed. Basically, they'll keep her passport and copy her other bits of paper etc. In the meantime, you send everything else off to Sheffield and wait for the outcome. You don't need to send your supporting documents to Thailand. We got our decision in exactly 12 weeks from the date of her appointment and her passport was sent back to her in Thailand.