On overland bangs there was an "unexplained" double boom over Coningsby/Horncastle a few years back, probably around 2005. It was probably one of va pair of F15c doing 1v1 high overhears but quite visible if you looked. Probably dropped it while descending.
TayC I believe the rules were no supoersonics within 30 miles of the coast it there was an onshore wind.