Does anyone know which airports on BA's network that have the same departure tax as Hong Kong?

I ask as I have an AVIOS upgrade voucher which I would like to use 2 X 1 ways for myself and partner. Hong Kong looked like a good option with only £50(ish) in tax, but im thinking of using my Amex 2-4-1 for HKG as the one way from GLA isn't the cheapest?


Any help would be appreciated.