I tried to buy some winter tyres last year but it proved very difficult as they were always out of stock. I notice Wiggle are expecting stock in November
Schwalbe Marathon Winter Performance Rigid Road Tyre Only £34.19 but I am not holding my breath. Obviously the market for these tyres must be incredibly small as most people don't venture out on bike in the snow and ice. Last year I did get fed up having to walk a considerable way to work as the trains weren't running, so I might consider changing the tyres again.
PS I was thinking I only really need a front tyre as a front skid is usually catastrophic and the back can skid around without too much problem. Any views on this? Obviously if I had a spare £70 for both it would be better.