how it works for rotary guys
The SAR Force is lucky in that there have always been plenty of hours to be had at a steady rate. There can be lean periods (especially in the Falklands where spares take a long time to arrive!) but 30-40 hours a month is typical for an individual who is available to work for the whole month (ie no leave etc). My personal best month so far was 53:20. Sorties can be anything from 5 minutes (certain airtests, or going u/s soon after take-off!) to 7-8 hours (assuming a rotors-running refuel is available at some point). No doubt some have logged longer sorties.
I have no direct experience of how the SH guys fare; what I hear is that people log a great many hours on dets but it's slim pickings during the time at home in between.