What surprises me most here is the fact that FR's Bus Plus fare is just £61!

I've just checked a couple of random dates and see KLM on lastminute.com for £1680.

Also, there are some pairings - like flying EK but earning into AS which is itself quite a good way of redeeming from the UK to HKG on CX - which I would be looking at.

But then you probably need to weigh up just how many hours you invest in the analysis of this versus what you save at the end of the day