Maverick,
Have a look at this
THREAD. As CyclicGal has said, there are relatively few opportunities for direct entry into civilian SAR (Bond Jigsaw were accepting winchmen with no previous SAR helo experience a while back) but if you don't ask......
The RAF do not accept direct applications for SAR crewmen. You can apply for WSOp and take your chances, but you could end up on fixed wing aircraft. Very few direct entrants are streamed SAR, but it does happen.
Mr P.