Sorry if I appeared to criticise the mate who did the low fly-by - that wasn't my intention. I don't know the specific case and was generalising.
I admit to having done both the post-Granby flyby over Base Hangar and 2 or 3 authorised fly pasts at the Secret Oxfordshire Airbase's Officers' Mess, but then I'd had the advantage of extensive and expensive low-level military flying training. The ac were at low weight and the fatigue consumption was budgeted. Whereas some other to$$er (who now flies 125s at a business airport near Ruislip) was guilty of 3 seperate flypasts at max all up weight - and he'd been let off a CFS posting because he said that he went 'tilt' if exposed to angles of bank in excess of 61 deg. Those 3 unapproved 'displays' flown by that untrained and unchosen idiot cost at least 18 months of airframe fatigue life.....