When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.
We had taxis long before GPS.
When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.