I don't know if you read these forums Mascot, but I hope so, else I'm probably waffling on to myself...
It's nice to see someone else visiting the stuff in Northumberland, especially adding new bits. The Beanley Hillfort looks a bit overgrown with bracken, but the outcrop has really caught my attention.
Loads of times, the hillforts in the area seem to be near outcrop with rock art. I don't know if there is a causal connection, but when I think of Lordenshaws, Chatton, Roughting Linn, Doddington, Old Bewick, there's nearly always both features.
There's got to be a good chance that there is/was something of a rockarty nature hiding in the Beanley plantation.
Oh aye, and welcome to tma :)