New British Traveller
Walpoole (& others) was a fictional name invented by Alexander Hogg, to make it appear many people were involved in his many part work publications.
This one was issued in 60 weekly parts, in 1783/84.
The maps were re-engravings, generally to a poor standard, of Kitchin's England Illustrated maps of 1764. The text across the base of the map indicates this is a later printing, but not when exactly (sometime 1784-1793).
Displayed scale of 20 miles = 42mm, or 12.1 miles/inch; actual scale = 10.8 miles/inch, ie 1:685,000.