I guess that part is inflated as you suggest, but you flew Qatar economy from LHR to BKK for I guess under 400gbp all-in. Even if the real cost of fuel was close to $100 there still not a lot of gold in the deal, the other mandatory fees essentially mean that Qatar have less than $100 per flight leg to cover their costs. Given Qatar is one of the best on this route I'd say you still got a bargain. BTW how was the dreamliner in comparison to the a380 iirc they were using 777s last time.