I would suggest a pre-bankruptcy (pre-Taylor) Schrade Old Timer 8OT or a similar folder. The steel is 1095 carbon and you get 3 blades that take a fantastic edge. You can find them on Ebay on a regular basis, and probably plenty right there in the UK, which will save you shipping. It was my first fishing knife and, if I hadn't been stupid and lost it, I'd still have it. I bought another 5 years ago and it's now in my tackle box.