I read somewhere that 80% of pilots ditch and evacuate the aircraft without serious injury and 75% of those perish from exposure. Not usre if the numbers are correct but they arent far adrift. If you are serious about reducing the risk it may be worth thinking about a liferaft.
I would be interested to know if you land in the Channel, the aircraft sinks (more than very likely) and you are adrift with only a lifejacket how long it will take the rescues services to find and recover you (assuming of course you havent landed alongside a passsing ship). Where is the nearest rescue helicopter these days?