'Gear up' approaches were occasionally authorised for specific checking of the runway caravan controller. Back in 1982 I was on a dual night check with Thrombo at Supholk's Phinest Phighter aerodrome and we were authorised for the check.
After rolling out on final during one of several circuits, there was an immediate reaction and red verey from the caravan - the controller was most certainly on the ball! No time for a Hadley box call to the local controller to advise us to check gear, just an instinctive and correct response.
I'm very surprised that the gear up Hawk wasn't spotted at Cranwell, particularly given that Hawk flying wasn't that much of a routine event at Cranwell.