Thanks for all your help! I've had the On-one packs recommended, would love the carbon fibre option, but not sure I can afford it. At the moment I've an ancient Marin Bear Valley (1999!) and I've been to Llandegla and Cody brenin, and loved it. I live in Sheffield and want to go out to the peaks more. Not particularly fit at the moment, so a light bike would be a major selling point!