Turkish Airlines is offering some good business class return fares from London to Bangkok at the moment. For £1221 return you’ll get a business class flight from London Gatwick via Istanbul to Bangkok’s Suvarnabhumi airport. This is pretty good price for flights originating in the UK: it’s common to find prices like this to BKK from European airports, but these obviously have the cost of positioning flights from the UK and you might even need to build in the price of a hotel for a night depending on timings.
I could easily find lots of availability for March 2018, as shown in the screen grab below.
However, the availability is much broader than this. There is good availability from the beginning of November 2017 until early December. The Christmas period is blocked out, but there is good availability again from mid-January 2018 onwards right though to the end of March, although after that the handy matrix view tool on the Turkish website doesn’t offer any insights on booking further out, see below…
The minimum stay appears to be only about four nights and there doesn’t appear to be a Saturday night requirement either, but why you might want to stay for a shorter period of time is beyond me given the nature of the distance and jet lag, and of course how enjoyable a stay in Bangkok could be!
Anyhow, yes, you can find cheaper fares than this from Europe to Bangkok, but this is pretty good direct from London with lots of options on the departure timings. The flights from London to Istanbul are on Turkish Airline’s B737 aircraft and then onwards on the B777. Both offer a good quality hard and soft product, with lie flat beds on the longer Istanbul to Bangkok sectors.