Great thread!
I used to be taken to LAP/LHR as a pre teen in the late 1950s before we left London in 1959.
Remember getting a bus tour of the "airside" the from newly opened Queens Building. I was really impressed when the bus came around a corner in the BOAC maintenance area and met a Brittannia, which promptly backed up to give the bus right of way.
Incidentally I just viewed LHR on Google Earth and was amazed to see that the latest photo has only one aircraft on the whole airport and that is the Concorde beside 27L, amazing and difficult to believe, as this includes the cargo and maintenance areas.