Lived in or around Harrow over various periods between 1980 and 1986, part of it on Bessborough Rd looking towards Harrow Hill. If the landing runway was 23 we'd get a constant procession of airliners, including widebodies and Concordes, passing our front window.
Later, using the commuter service from Euston, would be aware of odd days when there was a stream of airliners crossing the line in Kenton area. Stopped by mid nineties IIRC.