TK Maxx have in stock some Montane Primaloft smocks in stock in olive green @ £49.99. (....or at least the one near Preston did!)
They looked pretty neat: snug, warm, stuff up small.
The branch I was in - looking for new work shirts, a necessary evil - only had a few in 'large'. I did try one on, and whilst it fitted, it did feel a tad 'taut' across my shoulders when I raised my arms up.
However - for anyone of smaller dimensions than me, they could be a birrova bargain (for ref, I'm about 5'10", with a 44-46" chest....blimey, it's like 'Miss World' or summat all of a sudden! )