Thanks everyone. Apologies for not explaining the situation more clearly.
My woodland is in Wales. There is a public footpath which runs for 20 yards along the boundary before turning sharp left over a stile. At the turning a few locals are in the habit of continuing along the boundary fence, on my woodland while their dogs run around. There are many places along the boundary fence where people can walk straight into the woodland.
I have no desire to antagonise everyone by stopping this, but I equally don't want a host of prescriptive easement claims.
I also understand that if anyone, trespasser/kids playing/dog walkers etc is injured whilst on my land, with or without my permission, I am liable. Getting public liability insurance when there is a stream, old slate quarries, and a section of public footpath is proving a challenge.
I had hoped to put a sign saying something along the lines of ," you may walk in these woods with the owners permission. This is entirely at your own risk''.
I suspect I'm going to need a specialist lawyer again.