I do agree that this given position does look unlikely for any hillfort, but I must point out that our grid ref is only quoted as accuracy 3, so don't read too much into the position given, it could be several miles out. It is also a very old entry to our database, done before we had any accuracy values, so I cannot say where this grid ref came from.
However, I can find little else readily available on the web to back it up, other than this little snippet from Wikipedia.
"There are circumstantial indications (Pickford, 2003) that Grosmont may have originated as an Iron Age camp."
Unless anybody can add further information, I think we should move the position to Grosmont village (SO404244) and change accuracy to 2, nearest village.
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