A bit of rural evolution visible here. As you can see from the two upright stone posts this was originally a gateway. Long before my time back when the land was enclosed for agriculture. I do however recall the second stage of evolution which was the part walling up of the gateway to form a gap for the public footpath between the right hand post and straight line of stones a third in from it. The gap was there for decades until a few years back when it too was walled up and a very steep stone through stile put in for the footpath.
The stile was never easy to cross and is even worse now as one of the stone steps has broken off requiring a pretty tough gymnastic movement by the walker to reach the wall top.