The best footwear for hiking and backpacking while carrying loads under 40 lbs are a new pair of lightweight running, cross training, trail running, or outdoor shoes. I'm not sure what brands are available in the UK, but in the US New Balance, Salomon, and Merrell are top brands. Along with these light trail shoes one ought to wear a simple thin nylon or polyester sock, which we call a "dress" sock, which is relatively inexpensive. The advantages of a lightweight shoe are obviously less effort in walking, more nimble feet, overall foot comfort, and especially in the prevention of blisters.
A waterproof or Gore-Tex lined shoe is only suitable for Arctic/snow/freezing temperatures where hypothermia or frostbite is a possibility. For temperate hiking the light hiking shoe allows one's sweat to evaporate out of the shoe and were the shoe to get wet, one's own body heat would suffice to keep one's feet warm and dry the shoe, and even when wet a light hiking shoe doesn't weigh much more than it does dry.
I've hiked and backpacked in the Sierra for years in light hiking shoes, and in the last few years my wife and kids do so as well, so I know it works. Not having to take your shoes off to cross a stream, nor carry an extra pair of camp shoes, nor ever to have to worry about blisters... there's just no downside!
