After speaking with another neighbour who had the same issue with an identical looking wall nearby, it sounds as though it might not be the moment of the soil behind pushing the wall over.
When the other wall was repaired he mentioned it being pinned back into another wall that sits behind the facing wall. If this is the case here, then it’s not so much the land slipping down against the wall, it’s more sort of spilling over the top into the gap.
When the other wall was repaired he mentioned it being pinned back into another wall that sits behind the facing wall. If this is the case here, then it’s not so much the land slipping down against the wall, it’s more sort of spilling over the top into the gap.