I thought I'd put a review on here as it seems quite popular with MNetters. :)
I ordered the Plum in size M( in the sale 
). I am a size 10-12 (more often a 12) and 5ft 7" tall.
It is slim fitting but not too tight. I have worn a jumper dress under it and long sleeved tops with a thin cardigan. A chunky knit wouldn't realy fit but tbh I would not normally wear one on the school run anyway, as I walk fast and tend to get warm.
This week has been quite mild , temp wise and I have not been cold atall. I have worn it in drizzly rain and harder rain. Both times it was totally waterproof. The rain stays on the material, doesn't sink in. It's rather like the special coating on ducks feathers iykwim!(crazy analogy emoticon)
Sleeves are nice and long, perfect length for me. Cover over the top part of my gloves.
Hood is good too, if a little long at the fron. Sometimes I need to push it back a little when I'm stopped chatting to someone, but it's fine when walking, pushing pram etc.
:) :)