Morris and AoF are both correct in that whilst many tasks require attendance inside 15 mins to have any chance of success, there are plenty of others that need more investigation, and proper searches of the immediate area, before deploying the aircraft. However if, as some units now do, you cover a much larger area than before, your 15 min circle moves around with you and significantly stretches the boundaries of effectiveness, especially if you're any distance away from the "centre point" of your patch.
The big bug-bear, as
Morris has alluded to, is the ticky-box attitude of many forces in dealing with anyone considered vulnerable, or the top-cover required before AFOs get a move on with anything!! Keeping the aircraft noisily overhead some of these jobs un-necessarily is certainly in the ticky-box category and invariably wastes a valuable resource that should be able to immediately extract itself, if a job requiring speedy attendance presents itself, (and would be sensibly inside a 15 min window) where a delay would significantly reduce effectivity. {I'm not saying attendance at these mfh/AFO jobs is not valid, just that the time dedicated to some of them maybe longer than it should be.}
On a separate note, I understand from good authority that Mr Marshall was recently brought up to speed on the TFO "specialist" Winsor proposals and now appreciates that no "specialist" designation may well mean no "specialists" available . . . at all!