Actually the so-called 3 hrs really meant 61 minutes! SOC would have preferred us to hold RS60 but that would have meant considerable expense on 'Q' accommodation at the squadron, particularly overnight.
At Marham in Victor days I could hold 3 hours readiness at my house in King's Lynn. I would often receive a phone call telling me I was now at RS 60. No use me muttering that in fact I might not be at RS 60 for another hour at least,depending on the traffic, the execs didn't think along those lines, you were just expected to work miracles.
What do they call this operation these days, by the way? In my time it was Dragonfly, which later changed to Tansor. No doubt there is a new name for what is essentially the same job.