I have lived within 10 miles of LHR all my life.
We bought our first house in 1965 near Hounslow East tube station, between the two flight paths so am well aware of a/c noise.
I saw an early Concorde on an approach to LHR after diverting due to poor weather at its Bristol base.
It suddenly appeared beneath the clouds on approach and guess what, I saw no reports of it or mention of the noise.
Similarly, the last visitor, as far as I am aware, with a loud bark, was the RAF VIP VC10 which was the last reminder of really noisey a/c.
Again, I am not aware of any complaints.
I agree it is a small number complaining but their house prices are still soaring.