It is actually a 120 inch (plus a bit) plan, usually referred to as a "ten-foot" plan.
They do show good detail in gardens. It seems as though the roadside wall had once been Hadrian's Wall.
I've been going squiffy looking for a five-foot plan of Newcastle (1:1056), which should be around the 1850s and concluded it is not on NLS national index of town plans. So either it was not published, or NLS does not have a set for some reason.