TTN
but I think it was standard practice in RAFG at the time. I understand it wasn't pleasant,
The stuff they taught was the same at Bad K and Mountbatten. At the end of the day, the R to I bit and the conditioning that went with it was certainly uncomfortable, but it did not and could not get near what might be the real thing. What might happen to captured aircrew was skipped over really- there's no point in confirming that they'll stick yer balls in a vice. Rather, they concentrated on not being, 'played' by the interrogators, by sticking to the big four and, "I cannot answer that question".
At Mountbatten, everyone went in the bag, whether they were caught or not. Evaders were given a hot drink and went in the bag at 6 pm.
CG
(Present in the room at Bad K when Pyro Pete shot a Herc loadie with a miniflare!)