You are so lucky having old hedges to renovate, hedgebanks at that - I know it must seem a bit of a slog, but hedges are such a plus point. When I was growing up, the Government gave grants to rip out old hedgerows. I can remember me as a schoolgirl ranting at our neighbour for doing that, but his view was just that he was getting paid for it. He laughed when I said about the soil being blown away, but that's just what did happen in Norfolk - huge dust storms.
Here, we had no hedges when we arrived so we have planted them ourselves. We had to wait for them to grow - slowly, everything here in our high bit of Scotland grows very slowly - before we could start laying them, but already the sheep had browsed out the lower bits like yours. Most are now double fenced. We try to keep some big and bushy for the birds which like to nest at height and in good cover - it also protects against the sparrow hawk, although she has to feed her young I know. The laid stretches are now totally stock proof, but not fox proof unfortunately.
Sounds like you have a handy OH !! Mine is building me a giant wool shed, but it's taking forever, especially in this cold weather, when everything is stuck fast to the ground. In the meantime my house is full of wool waiting to be dealt with once the palace is built.
Good luck with all the work you have to do - it never stops but I'm sure you love it as much as we do.
Good tip about the lime for sheeps feet, landroverroy.