The FlightCatchers website has a strong offer for return flights to Hong Kong from London for £338, with departures at that price at the end of November.
The flights go via Beijing, and are around £100 less than you might usually pay for this route. They do have other dates, and alternative departures, including Manchester for a bit more.
We didn’t know FlightCatchers too well, but they have a 4-star rating off 4000 Google reviews, so we probably should have.
As always, these deals could change or expire at any time, but they were accurate when we checked.