Thank you for that; it's more or less what I thought was the case for my specific situation. I'l leave the cold weather tyres until I move somewhere less clement when I retire. (The hill is the lane past the Falcon, by the way; more of a slope really, I suppose, but the 90 degree bend after the tunnel stops one taking much of a run at it).
I couldn't 'arf do with some tyres to grip in snow and ice on my bikes, though....
BOF