Thanks guys. As we arrived at Loch Ness a small group of 'wild' swimmers were just returning to the car park so I guess the swimming season is under way despite the temperatures (we had some snow & ice overnight). The water temperature only reaches 13C in the summer and I guess is more like 4 to 6 C in winter. It's such a vast amount of water and so deep that the core temperature hardly changes with the seasons. Obviously the shallower bits (where Mungo the monster went for a dip) have a wider temperature range. It's difficult to keep certain breeds of dogs out of the water regardless of weather conditions and that certainly applies to English Springer Spaniels despite him having very little body mass.