I notice that the geocoding of the following doesnt seem quite right. However I recall a discussion some time ago with Ivor that in there are sometimes errors with Google maps.
http://london.openguides.org/index.cgi?Harcourt_Arms,_W1H_4HX Streetmap gives 51.519512 -0.164186 ) Open guides has 51.519003 -0.162582