After all they had never tried to escape at the two previous houses.
How wrong we were!
Our Kelpie Labrador cross Jemma was soon burrowing under the fence.
As soon as we filled one hole with bricks she started digging in a new spot.
After a bit of research I found a good solution was a 500mm wide strip of heavy plastic mesh.
This was fixed to the bottom of the fence panel and sloped back into the soil at an angle of around 45%.
Fairly easy to do, if you install it before you landscape.
This means that you can still put plants close to the fence but the mesh will stop the dog trying to dig under the panel