It's a been a long hard slog trying to get my neighbour to raise the fence height by 600mm as his land is now up higher than natural land height. After getting the lawyers and the Private Certify Authority involved, they finally saw sense. It was much easier for them to get in from their side. They actually ended up pulling out their soil pipe so that they could did the holes. Their soil pipe was pretty much right next to the bore holes so probably would have broken anyway.
Looking at the holes from a different height, stood on the wall. They've decided to do the entire length in one hit including Charles (next door neighbour) as well.