Here is the solution - get a pair of long (cycling length) undershorts that reach to just above the knee (tartan if possible, plain black if not) - available in most sports shops. When the temperature drops to -20 C or less, even a heavyweight lined kilt probably won't help.

Incidentally, anyone ever come across a pair of tartan cycling shorts? I would like a pair - for the bike!

Cheers,

Niblox