There's not a tremendous amount to see, just a big mound with a moat round, and some wooden steps to the top.
For years it was assumed that this mount had had a large wooden tower on the top surrounded by a defensive palisade or wooden wall but in 2011 these assumptions were questioned by evidence (or lack of it) found during a dig led by Dr Carenza Lewis from Cambridge University as part of the Managing A Masterpiece project (she is also well know from C4's Time Team programme). (More information about the findings of the dig can be found here).
They found that it was more likely to be a look out post that was not permanently manned and was possibly built by enlarging an existing bronze age burial mound.
The views from the top are certainly impressive.
It seems to have been built about 1100-1150 and would have been very prominent in this isolated area and probably sent a clear 'go away' message to any unwelcome visitors!
I'm not sure we'll ever find out exactly who built it but I'm glad I stopped and walked up it.