As a regular commuter on the BA NCL-LHR run, I cannot help but observe that by the early evening, it is now almost normal to expect at least an hours delay, sometimes more, due to "delay on the inbound aircraft". Presumably this has built up form the cummulative effects of the early morning flights. Too many flights and not enough resources, ATC included, to turn them around fast enough. This is yet another nail in the BA "premium business" coffin.
Sadly I have seen all aspects of the whole service deteriorate over ten years, to a point where reluctantly I shall have to consider either the dreadful railways, or flying myself to Biggin, and foregoing the evening champagne!!