Abi, I suggest you look at flying with one of the ME3 (Qatar, Emitates or Eihad) carriers and book into business class from AMS to BKK when they offer a seat sale. Infinitely preferable to KLM who offer a very inferior product in all cabins. The stopover, if short, helps avoid jet lag and DVT. My next visit to Thailand is in November from London and I am taking a positioning flight to AMS and then fly on from there with Qatar in the business cabin for circa £1,000 return. Excellent value.