You're ignoring the main issue, Ash. It isn't the temperature or the amount of rain in this godforsaken country. It's the lack of sunshine that is the killer.
The sun is good, Ash. It prompts physiological changes which make you feel better, happier. Everything is better under sunny blue skies and England has far too few of them.
Which is why we have pubs, of course. Well, that's my theory anyway.
It is a proven fact that hot weather kills more people than does cold weather.