One obvious question.....are 20 aircraft enough?
Take for example the Boscastle flood. Something like seven Sea Kings used at the same time. Or the Fastnet race incident. How many were used there - something like 15 combined from Navy and RAF??
If you assume the usual degree of downtime for servicing, is there enough depth to cope with a major incident? At present the services have available reserve aircraft from the training squadrons (as happened with the Fastnet rescues) but presumably with the new regime they won't be available as backup.
How many aircraft were involved in rescues during last weeks snow? Or still are for that matter? It seems to me that it wouldn't take much to overwhelm 20 airframes, especially if requested to support hill farms / cutoff villages