In reply to RoK:
Don't discount Rohan trousers --- they used to do at least one technical softshell pair every year. They currently make a few sports-oriented pairs of trousers for women in their special shorter-leg range but it might be best trying to get to one of their shops and check the fabric.
Gearforgirls have a few that look suitable and you can search by garment size. They have free returns, which take about a week, and are really efficient. They may have a sale coupon for this month; if I can locate it I will post it.