There is a big difference in how various airlines fly approaches.
I stayed at a relative's home in Battersea last summer for several days. I guess this is about a 10 mile final for the westerlies at LHR.
We slept with the windows open and could not believe the noise from the early morning long-haul arrivals.
After several mornings of been woken up by this racket I got out of bed to investigate.
The noise was being created by 767s/777s/744s/330s of various foreign airlines who were flying straight and level with gear and flap down and an associated increase in power to compensate.
The biggest culprits belonged to US companies. From the other side of the house I could see BA and Virgin aircraft lowering their gear at a more sensible range - established on the glidepath and, I guess, about 7 miles from the airfield.
Hell of a difference to the local noise imprint.