You probably thought I was all talk. I've been trying to do a diagram clear enough to show the fox proofing. The photo here doesn't quite show how it works.
The whole system is a variation on what we've probably all seen before.
Here's my artwork
If you need the info I hope you can see it clearly enough. Here's the explanation.
On the bottom of the fence at a 90degree angle on the outside of the run you lay mesh and attach to the base with gal rings, wire or what ever. It doesn't have to be buried. Rolled top weld mesh is what I saw. It has no sharp edges. About 300mm plus is enough. The fox can't dig and keeps moving along.
On the top because the chicken wire supports move the barrier flexes and the fox climbs to it, it moves, he drops down.
I hope you can understand.