I constantly prowl the local surplus stores for novelties, curios and relics. Sometimes I actually find useful stuff. I see more good packs than anything else, probably, and they are mostly all at good prices. Only I end up buying so many! But anyway, that's where I got my PLCE bergan. My last pack--I mean my most recent pack--is a Swedish external frame pack. It has a relatively small green nylon sack, so you have to put your bedroll underneath. I also have two older bergan type packs, identical except one is nylon, the other canvas.
I also buy all smocks that fit that I find, or at least it seems like I do. I have about five, including an arctic windproof, plus a reproduction WWII pattern windproof smock in camouflage with matching trousers. I have also a bag full of shirts. I have found No 2 dress poplin shirts, Dutch DPM shirts and German army OG shirts. I haven't bought any but one surplus store has British blankets that are about twice as thick as an American army blanket. I can only assume it is twice as cold in the UK as it is in the US.
I have a lot of other British kit accumulated over the years but more of it was either purchased directly from British stores or from specialist militaria dealers here. However, there are things I've never seen so far that I would probably snap up if I saw any. That would include current issue fleece items and more lightweight trousers and probably another pair of battledress trousers. I'm not sure I'll live long enough to wear out the ones I have now, however.
As one contributor wrote, buy spares. So I do and then some!
Every now and then a quantity of surplus will appear then won't be seen again. At one time one of the local department stores had a lot of 1950 pattern khaki drill trousers. I had a couple but that was now close to 30 years ago! On the other hand, there are things I've never seen in a surplus store, including any British boots or OG shirts or any British wool shirts (flannel shirts) of any pattern. I have seen lots of battledress and No 2 dress trousers and, lately, DPM combat trousers but they have all been too small. Wool jerseys show up with some regularity but they are all small and in bad shape.
And that's the way it is.