Have a look at PHD designs, but speak to the bank manager first...
or not as the case may be...
A lot of good gear is available, but it's not from Blacks et al. Cotswold might have a bit (depending on store location, as the range is tailored to local markets, so the stuff in London is going to be more fashion orientated compared to Betws Y Coed or Keswick) I'd avoid Snow and Rock (Slush and Rubble) as their gear is much more snow sport orientated, and the same with Ellis Brigham's.
My recommendation would be to look at the following places:
PHD Designs: Online company that doesn't have a shop front presence, made in the UK, lots of cold weather gear for both Alpine (fast and light use) and expedition (heavier and often designed for Polar/Himalayan regions)
Tamarack Outdoors: Company specialising in bushcraft stuff, run trips to Scandinavia, and based in Lancashire.
Trekkitt in Hereford; General outdoor equipment store, have a good relationship with "the base" in Hereford.... so lots of sand and black coloured equipment
All of those places have staff who do the stuff they're selling for (well, with some exceptions... I think that some of the places that Trekitt's customers go to are a bit off the beaten track, and the FCO don't encourage travel there for your own safety); Tamarack in particular will be worth talking to about cold Scandinavian travel.
From those places I would have a look for:
a high R-rated sleeping mat (
Exped Down mat or similar, the highest in that range is rated at 9.0, my MegaMat is 9.5 but is perhaps a bit bulky for backpacking) as that will insulate you from the cold ground.
a sleeping bag with a comfort temperature of about -20*C, so from
PHD you're looking at one of the Diamir 700 or Hispar 600's (and the £550 mark) or something from the Rab Andes Range at Trekitt, or the
Helsport range from Tamarack (again around the $500 mark) My down bag (a £200 Mountain Equipment bag... in 2002) has lasted about 12 years, but it was used pretty solidly for months at a time, whereas my synthetic one (an Ajungilak Kompakt) lasted from 1995 to 2002, the final couple of months of use for it killed it... again, it was heavily used for a couple of months at a time.
Clothing is a much more personal choice; I'm a big believer in layers of thinner clothing rather than a lot of thick ones, and dressing a bit cool to start with on the assumption that you'd warm up, minimising sweat build up - which will cool you down as quickly as you warm up. When I used to do whitewater canoeing and kayaking in the UK I'd often be out in the winter in a drysuit with anything from a thin thermal and a pair of Ronhill's, to 3 layers of 100-weight fleece on my top half, or if I was bank coaching/jumping in a canoe every so often then I might even have a down jacket or a
Buffalo Type Jacket on under a dry suit.
Hope that helps,
Ed
(10 years Outdoor Ed and activity leadership/guiding, 4 years outdoor equipment retail experience in the UK)