I have a triple A flashlight (yank talk) made by a company named COAST. It is made of very heavy aluminum, with LEDs and it is extremely tough and reliable. Cost me about 25 dollars U.S. I suppose that would be about 19 or 20 Pounds. One of my favorites.
Another possible option, would be the mini Mag Light. They are sold everywhere over here, but I'm not sure about in the U.K. They are small, light, (aluminum) and very durable. I have had one for probably 20 years and nothing has ever gone wrong with it. (Now for the good part: You can buy a kit for about 9 dollars U.S. that converts it to an LED.)
I converted mine about a year ago, and am very happy with the conversion. It is simple, just change the front reflector/bulb, and you're done. If I hadn't been able to convert it, I would have retired it but the conversion gave it a whole new lease on life. Not as bright as my COAST, but quite bright, and I think the batteries last a bit longer.