Personally when I found the cache, there was little to no chance it could cause damage. But this never the less is a most valid point John
Having revisited the cache tonight, I have moved Emma a few meters across the road. Moote is correct "there was little to no chance it could cause damage", however, there was a wobbly stone on the road side of the wall, which I suspect a number of people had tried first. In isolation that is not going to affect the integrity of the wall, however, repeated removal of this and perhaps other likely candidates on the road side of the wall might have a negative cumulative affect on the wall.
Note also, that in addition to being mortar-topped, the wall is also mortar-ended:
This look like a dry stone wall to anyone?
i will comment on the last remark only.
to me this wall appears to be of drystone origin which has been morter ended and mortor topped to prolong its life. I may also be wrong on this as i am neither a farmer, drystone wall builder or knowlegable local. most drystone walls i have seen use the stones on their sides/ends and wedge each other and the likelyhood of a single person being able to physically remove a stone from the wall while it is intact is very remote due to the huge amount of weight on each stone lower in the wall. however, to contradict my own statement i observe that the stones in this wall seem to be placed and stacked on top of each other in a way that may not mean the wall has the same structural properties of a dry stone wall, making it more vulnerable to lateral movement and collapse.
however, the point i believe remains this:
is there the potential of damaging the wall in the short, medium or long term by using it as a cache stash. I would guess that the answer to this would have to be yes. unless the wall was constructed with the express requirement that a particular stone should be made removable. i doubt that this was the case and as such the wall depends upon all stones in structure to maintain integrity.
someon must have felt the wall was vulnerable or it would not have been topped and ended.
at the end of the day regardless of my personal feelings i would bow to the wishes of a moderator. full stop.
that is all
kind regards
Paul