I'm sure some of these were carried out in about '69 by a Lightning from Farnborough. I heard one that year from my parents home in Chesham, Bucks although I didn't realise what it was(I thought it was thunder - mid august - we had hot sunny weather during the summers in those days - Labour have a lot to answer for) and only found out what it was from the newspapers next day. The supersonic run had apparently started from near Reading flying due east. I was told about this and other runs (by Honey Monster I think) when I arrived at Farnborough a few years later.