Good news. The walls that have stood for near 300 years don’t need to be underpinned. They’ve held up this long, no reason to think there’s not a few more years sitting just as they are.
However, the exposed sections of earth will be encased in reinforced concrete to protect them.
Structural engineer Peter Bartlett of MDHP commented that the compacted red earth was Cotswold Sand, very good for growing veggies… and in this case fine support for old buildings like 2 Hillside.
So, it seems, this is one house built on sand that the big bad wolf is not about to blow down.
Before and after pix: