Sorry, should have added in original post that our BA0026 is an inbound leg of an Avios/AMEX 2-4-1 redemption booking on BA.
Ideally, yes, we'd have returned to the UK on CX but unfortunately that option wasn't possible using the above.

I guess I'm trying to figure out whether people who regularly use HKG would risk a 2:30 non-protected transfer from a cash CX booking to a BA reward booking?