LHR is a hateful place to be. Frankly it is little wonder that the ME carriers are doing so well, not having to transit there works wonders after you have slummed it in an economy class seat for the last 24 hours. As mentioned even UK passengers don't need LHR anymore with EK flying to many regional airports which would be much closer to most people.
The days of BA needing to provide a feeder service to pax transiting in LHR are all but over...