Hi
What sources did you use for this edit? 

It appears to be a purely armchair edit and has undone edits made by the National Trust using on the ground knowledge.

Whilst it may not have been perfect, it is clearly a work in progress done with on the ground knowledge.

A comment on the changeset would have been preferable.

You should not assume the definitive map is accurate, in OSM we map the 'walked line'.

Not sure what you mean by "If not ground truth but only legal, it should be removed or tagged different" but how do you know they there is no ground truth. It is rare for rights of way over farmland to be visible on imagery, ground truth are the gates/stiles and waymarks which need to be surveyed.

Cheers Phil
 