What needs to be done to the milestone?
Before you contact anyone, think through what might need doing; how will that affect the milestone and how will it be cared for in future. Historic England advice suggests that “The present day context of each stone should be carefully considered before any action is taken; it may be that a stone has 'grown old gracefully' and now sits so comfortably in its environment that any form of intervention would be unwelcome. Furthermore, it must be appreciated that some interventions, though well intended, will be irreversible and thereby change the stone or metal forever."
But if you consider that care or repairs are required:
1 Is it overgrown with weeds/ivy?
2 Is it covered in moss or lichen?
4 Has it fallen over?
7 Does it need moving to a safer or more convenient location?
8 What about its future care?
9 What about Fund raising?