Genghis
Being able to swim is not the point. Surviving a ditching (especially in the cold waters around the UK) is more about being able to deal with "swim shock" -- fighting the urge to breath in, triggered by the cold water on the nervous system. Most people can manage about 6 seconds before they give in (even if they can hold their breath under water for minutes in controlled conditions). This means you need to get out of the aircraft and get your head out of the water within those few seconds. Also, if you are in fixed-gear tricycle undercarriage aircraft, there is a high chance the aircraft will flip over when it hits the water. You are then faced with being inverted, possibly sinking, and then having to manage a safe exit from the cockpit without giving in to the urge to breath in....If you are enlightened enough to be wearing an immersion suit, you actually have the added problem of being buoyant inside the aircraft as it sinks inverted i.e., you may be pinned against the floor. Net: as much as I would hate the prospect, the best bet would be to abandon the aircraft and not attempt to ditch it. That's what the RAF taught me, and that's why I wear an immersion-suit, life-jacket with attached dinghy-pack, plus parachute, whenever I fly over open water...which I do most times I fly since I live on an island.
So, in this philosophical debate, I would suggest the solution is to point the aircraft out to sea (to avoid the bystanders, as you rightly assert), and abandon above a safe altitude (if you have the appropriate kit to do so, which you should have).