Having been an active RNLI Lifeboat man in Jersey, Channel Islands and on the south coast of the UK I *have* been trained well, and I *have* been alone in the water with nothing more than a lifejacket (ok and drysuit/wollybear) and I *have* been winched up to Rescue Helicopter, and I have been out at sea on Christmas day - and *in* the sea on rescues on new years night... and completing the MNTB Sea Survival course (um, 3 times now)...
I have also been out at sea, 2 weeks away from land on a cargo ship at 18 years of age...
...and would I want to jump in the sea for a real emergency, with my flying clothes on - HELL NO!
Its hard enough, cold enough, stressful enough, when its for exercise only!
I fly often from Jersey to france, did most of my PPL over water in the islands, but have not yet done UK to Jersey... thats out of sight for too long for me.
Here is the link to the long running thread on PPRune about this:
http://www.pprune.org/private-flying...ll-you-go.html