In reply to Alex the Alex:
One approach to Scottish winter kit that lends itself to all levels of budget is the microfibre and insulation combination that is unified in implementations such as Buffalo and Paramo. Essentially, it is the same as the Ventile and woollens of the 1950s but using lighter modern fabrics.
If you have a microfibre windproof layer treated with water repellent with a layer(s) of wicking insulating material, such as polyester fleece or polypropylene, under it then it should behave in the correct manner. The outer layer will resist wind and rain and the inner layer(s) produce a temperature gradient that will drive moisture outwards.
You can do this pretty cheaply but accurate material assessment and selection is vital. The alternative is to pay for Paramo or Montane to do the thinking for you.