I feel some of you maybe missing the point of what a Nimrod bought to the SAR mission that a C130 or any other presently available UK asset lacks.
In my 30 odd years, i think i dropped ASR sets on less than a handful of occasions.
What was much more important was the relatively quick flying time of the aircraft, to reach a datum before the Seaking, perform a search and vector in the helicopter, who at PLE, did the lift and headed straight home, At max range he doesn't have time to search.
Also, the Nimrod with a trained 12 man crew , (large disasters practiced in the simulator), 2 HF boxes, 4 V/UHF boxes and an FM radio, had the ability to control multiple assets and this is where the Nimrod shone. Alexander Keiland and piper alpha being two incidents that come to mind. With 10 helicopters in the area, multiple ships, the coastguard and the RCC to talk to, the mission could just not be done without the endurance, sensors, radios and crew size that the Nimrod provided.
Dropping an ASR was just one small part of the mission.
Of course, the SAR crew were also on stand by for other missions, mostly covert, that came up at very short notice but that was a bonus of having such a capable and multi role aircraft available on one hour stand by. I probably launched on more Ops missions rather than SAR missions while holding SAR.