Hi j_r_m,

I think the Air Asia flight London->KL makes alot of sense if looking for a cheap one-way option, as you will find the one way options on most major carriers are expensive compared to returns.

Do consider the Air Asia are a low-cost carrier flying from Stanstead, so beware of extra charges for baggage, early boarding, onboard food/drink etc.

Earlier this year I saw competitive fare to BKK with Jet Airways via Mumbia (approx 480GBP return if I recall correctly), so if you wanted another option with a stopover in India you might want to investiage this.

I've also seen (and booked!) Thai Airways direct flights starting at approx 550GBP. Eva airways have also had competitive fares, again direct.

Hope this helps.

Regards, Graham