BA extra seats
Think this was done a couple of years ago.
I agree with EK77WNCL in that the people who used to use the LGW and STN routes are now using the train, car, bus etc and only perhaps a few are using LHR.
I do believe that nowadays however the majority of people on the LHR are connecting passengers. Thats why timing and frequency is so important.
If your a regular on this route you will know that is usually very busy.
Re loyalty, I believe there are still a number of Executive Club members using LHR to connect to Australia etc so they have not all gone to EK