I`ve found this in the SMR:

National Monument No.33951

<I>A recumbent tabular stone 1.4m in length situated on the edge
of Overton Down includes grooves and a dished area consistent with its use
for the shaping, whetting and polishing of Neolithic stone axes. Excavation
around the stone in 1963 demonstrated that it had originally been upright,
whilst an iron wedge and a coin showed that it had been split in the 13th
century AD.</I>

So it is protected (theoretically, within the law) and there`s no need for secrecy, is there?

baz