Sandy tried to catch me out with the old Citroen suspension unit ploy..
It was a double bluff by Sandy Sanderson, who was an instructor there at the time. He’d started to include bits of stuff that weren’t ordnance related to make us tie ourselves in knots trying to classify them. Then he showed us the Hawkins mine, upside down out in the garden...
Since then, I’ve found that the ‘group, sub-group, role, hazard’ system of recognition is something that has been incredibly useful in all the odd places I have found myself, and seems to be pretty unique to people who have been through the British system.
It didn't work!