We stayed in London for a couple of days after camino last year and walked from Marble Arch to the British Museum one afternoon. When we came out in the early evening we came out of a different entrance (however the back and front seem to have the same Facade). So we being quite unsure in which direction we should start to walk asked a young office worker going home, if she could direct us in the right direction to Marble Arch!
She looked at us both worked out we were past our sell by date and suggested the Oxford street Tube station! My wife replied "Oh no we prefer to walk," then the young lady said "well you can go along there, but it is a long way must be at least two miles." We both thanked her and arrived back at Marble Arch about 30 minutes later. Sometimes some people think just over a mile is a long way!!