The only other Supersonic runs over land in the UK were from RAE Bedford along a 'corridor' following the Bedford Levels.
Not quite. In development testing of Concorde one of the prototypes or pre-production aircraft operated a series of flights down the whole west coast of the UK (from the north of Scotland to Cornwall) in the early 1970's to measure the boom at ground level. I remember hearing them while on holiday on the Isle of Arran.