In reply to Fiona Reid:
A further +1 for Paramo. I find the Aspiras a bit too heavy and warm, so got Paramo to make me a customised pair of the standard Cascada trousers, adding in crampon patches, snow gaiters and under-foot bungee cord. Brilliant. So cheap, incredibly comfortable over a wide range of temperatures, particularly with those big side vents, holes easily repaired, ridiculously breathable, don't wet out, etc. All I wear under them in winter is a pair of Rab MeCo boxers. (Well, 2 pairs if anticipating >1 hour belay stints!) Am defo going to add knee pads next time due to my grovelling winter climbing "style", however!
Important to try on for size first: I'm large for most manufacturers' trousers in terms of waist and thigh size, but medium for Paramo. They do the Cascadas in differing leg lengths which is well handy.