Hi, I did 28 days also in January 72...watched Queen Elizabeth burn and keel over from cell window.
I know what you mean about the screws but there was one or two decent ones who I found reasonable but certainly a tough regime.
Having no door on the toilet was very ignominious in the eight man cell and ‘bumping’ the concrete floors was a pain.
The worst part was seeing the lights twinkling at night in Kowloon from the cell window.
Remember having to shave our bed side stools with the blue Gillette razor blade to get the wood white and clean. ‘Short arm’ inspection and a haircut every week. The barber wore a mask, allegedly for hygiene reasons but I reckon it was in case we recognised him when we got out!
Assault course, field punishments and the PT were all ‘taxing’ - I came out a lot fitter than when I went in!