Another vote for TKMaxx. Ds has worn his ski jacket (managed to get a Trespass 3-in-one) for the last 3 years as his winter coat (and summer, in its constituent part) and it now has holes in it, so I think we got our money's worth.
Unfortuantely Trepass no longer seem to do the 3-in-1. It's been such good value, I'd even be prepared to pay full price!
If you don't get stuff that's too bright, then at least the jackets can double up as winter jackets.
TKMaxx does salopettes, thermals and gloves.
Personally, I like silk socks, which I get mail order from Patra.
The rest you can probably already make do from clothes you already have - lots of thin layers. For example, in cold weather, I wear a long sleeved thermal (M&S), a thin wool turtleneck jumper and a long sleeved T-shirt under my ski jacket. I am also very cold blooded, so whatever the weather, I also wear long johns under the salopettes - but you oculd just get awy with tights.