Danny, I was never harshly treated at CATCS. Indeed, my main recollection of the Instructors was their determination to get us through the course. The "beatings and abuse" came during OJT on my first tour, albeit rarely, until I had been knocked into something resembling a 'proper ATCO'
My only 'Instructor clash' occurred on my GCA course, when a certain fg off [later AOC MATO] insisted I set the rheostat on the Sim to display range rings every mile. I reset to show at 5 mile intervals, as I was headed for an MPN11 truck where only 5-mile rings were available ... and I found the display hard to work with all those concentric circles! After 'a bit of a barney', I reluctantly did as I was told and, after the Exercise, complained to our Course Commander, one Harry T of your acquaintance. Inevitably he supported the Instructor