Alpkit sells itself!
They have always been a nice company to deal with, and its decent kit and decent prices. Unfortunately, its a good hours schelp for me to go to their showroom, but if your close by, you might get a bargain, and if nothing else, you can try clothing etc on for size.
I'd still recommend putting a sleeping bag inside a pack if possible - its something you really dont want to get wet or damaged. And if that means getting another pack, its often cheaper and easier than buying a new sleeping bag.