http://www.snugpak.com – Snugpak do a range of great sleeping bags – take care to choose the manufactured in the United Kingdom ones though. They also do great UK made cloths (just some jackets, trousers and hats are made in the UK), so likewise with their clothing take care to choose made in the UK. Items that are UK made are clearly labelled as so on their website. You can even filter to just UK made products. Only some clothes, some sleeping bags, some bivvi bags, some sleeping bag accessories, some hammock blankets, and a stuff sack are UK made; everything else they sell is imported.
Snugpak are based in the heart of the beautiful Yorkshire countryside. The Sleeka jacket below is made in Yorshire. It is made using a fabric they call Paratex Light which is lightweight, windproof, water repellant, breathable and wicks moisture and is insulated with their Softie Premier Insulation (which was developed and is actually made in Switzerland). This retains heat even when wet, is washable and high loft. It comes with its own stuff sack. The minimum temperature range given is -5C (comfort) and -10C (Extreme). Long enough and very lightweight (170g). The Sleeker has 2 large zipped outer handwarmer pockets and a large zipped internal pocket. The Snugpak Sleeker is simply a fab jacket and mine gets a lot of use.
Sub Zero Technology Ltd. manufacture thermal underwear, thermal baselayers, thermal midlayers, merino wool base layers, childrens thermal underwear, softshells, balaclavas, fleece and waterproof Jackets in England at their Leicester factory. Not everything they sell is made in England, but mostly they do label which items are UK made on their website so you can easily find their UK made stuff. If it does not say made in the UK then it is probably made abroad. Available at the Sub Zero online store – http://www.subzerostore.co.uk
It is hard to find a UK made fleece jackets these days (companies like Berghaus and Karrimor now make all their products abroad; they used to manufacture in the UK). Sub Zero still make their fleece jackets in the UK. There is a review of a jacket here. Some other companies make fleeces in the UK are: