PUG,
Its 1 in 3 not 1 in 4. Including RMs it is not too difficult to see about 6000 RN deployed at any one time.
Re your SARF, where else do they deploy apart from the FIs for 6 weeks??? I don't wish to decry the amazing flying they do but when the first PFI study was done about 7 yrs ago there was no operational justification for retention of the SARF. There was then a lot of work done to "operationalise" it by talking about combat SAR and getting SH crews to cycle through the SARF on the basis of taking SAR skills into the front line. The RN case was totally different as all RN SAR crews are drawn from the operational front line where SAR skills are part of the sea-going role.
Way off thread but this is possibly because really no-one gives a T*** about the future structure.