Im a bit late to the party - used to travel to LHR as a teenager in the 70s - the 140 bus of course! Hanging out of the front windows and unscrewing the light bulbs......
Sometimes also used to bike from South Harrow with mates and spent time riding around the perimiter road - one spectacular sight was a whole line up of 747 waiting to depart the then 10R - BA-AC-AI-PA-TW - I wish Id had a camera handy!!
Later in life actually worked there for various foreign airlines - I remember one stormy night 05R was being used (late 80s??) and the captain on the flight I was handling kept asking if he could use 10R but was out of crosswind limits - he didnt look too pleased about 05R - but departed all the same!