Hi Paul810

For Summer Weather - Nosquito Convertibles
http://www.craghoppers.com/CraghoppersSite/product/Mens/CHJ183R.htm

For Wet Weather - German Army Goretex Overtrousers.
http://www.surplusandoutdoors.com/ishop/877/shopscr1533.html

For Really cold weather - British Army MOD Issue Softie Thermal Reversable Trousers Desert/Olive.
http://www.surplusandoutdoors.com/ishop/877/shopscr2573.html

For Dry Cold Weather - West Winds Single Layer Ventile Trousers
http://west-winds.net/single_trousers.htm