In terms of SAR support for FJ trails I would offer the following observation.
In the days when dedicated SAR provision was provided, in terms of a Nimrod MR2 that formed part of the overall trail package, on numerous occasions when the Nimrod went u/s the trail elected to continue without dedicated SAR cover.
That is fact, the next bit might be more contentious and open to contradiction, but I believe the decision to press on was often based on the insistence of the senior FJ officer present, usually a Sqn boss.