If you have a generous bum and smaller waist then Craghoppers and similar, 'mainstream' makes are unlikely to fit, at they give you loads of waistband at the back but pull in uncomfortably across the tummy. If this is the case for you try Sprayway. Dearer than the others but a beautiful fit, mine have two layers, a very thin fleece that makes it nice and warm inside with a waterproof skin over the top. And they last well two, I bought mine two years ago but they are so comfortable I often wear them as normal trousers as they don't look as casual as the likes of craghopper. Despite this they are still like new and I can see years of use in them making them well worth the initial extra cost.