Preparation
LegalApproach, it sounds like you had done about as much as possible in terms of preparing for the eventuality. In UK waters, hypothermia is the killer, so proper preparation, wearing of survival (dry) suit, carriage of life raft, etc, is necessary.
How many pilots of sep's put the life raft in the boot? Or don't wear life vests? Or don't carry emergency flares or EPIRB? All these things can contribute to one's survival if the inevitable happens.
A further consideration is that on water (which, barring swell & waves, is at least in general flat and unobstructed) you do have a reasonable chance of being spotted by SAR personnel.
I flew some years ago over the Finnish steppes, which were covered in about 12-foot high close-packed scrub. One's sep would have disappeared in the scrub and I dread to think of one's chances in case of injury.
DT.
P.s. LegalApproach, would you let us know the outcome of the investigation? I note the comment in your story of the "just out of 50 hour" bit. That always sounds a bit ominous.