I emailed the Rural Archaeologist at North Yorkshire County Council. They replied immediately and informed me that the stone is not their responsibility as it's within the North Yorks Moors boundary, so it's the responsibility of the National Park authorities. They did suggest I let them know, and also inform English Heritage as the stone is a Scheduled Monument.
So I emailed both organisations.
Today I received an email from Graham Lee; the Senior Archaeological Conservation Officer for the North York Moors National Park Authority. He said:-
"Thank you for your report. Yes, it is a scheduled monument and we are fully aware of the situation. However, Scheduled Monument Consent & an excavation to record the site will be required before it can be re-erected. The process has been started but will take a while to complete."
So... Here's hoping! :D
English Heritage haven't replied yet.
Cheers
Dave