Can't help you with the first one, but to answer the second, there isn't really a gap to fill. The winchmen on British (and other) rescue helicopters are more than capable of resolving pretty much every incident which crops up using their existing techniques and equipment. Bear in mind that winchmen may well come off the wire if the situation requires it - there's nothing forcing him (or her) to stay attached just because the job description is 'winchman' and not 'rescue swimmer'. If the rescue diver role was so vital, why do you think British SAR aircraft don't have them? No offence at all to the remarkable individuals who do the role - they are very brave and certainly a desirable part of the crew, but not essential in most cases.
I want to really rescue people
No doubt you didn't mean to cause any offence, but be careful with your wording - suggesting that winchmen don't really rescue anyone might ruffle a few feathers! Most SAROps in the UK SRR are overland or coastal anyway (I don't fancy a rescue swimmer's chances of success if he jumps out over Torridon or the White Cliffs) and the variety of challenging, exciting and downright dangerous rescues which British winchmen (and others elsewhere) conduct is enough for most people!