I agree with CWBalmer, its got to be done some time, although eventually it can feel a bit boring in all fairness, but on a single day you’d be fine, but going too often isn’t great. You will see plenty of airlines that don’t fly into any other UK airport, and there are 747s all over the place. The great thing about LHR is that its constant, aircraft everywhere all the time. Its true that there are BA aircraft everywhere, but then its no worse than CDG or FRA in that respect.
If the aircraft are using Rwy 09 then it isn’t bad to make your way to that end of the runways.