Although I’m not walking to Brighton myself, I created a map to be able to find my friends on their way. You can browse the map in Google Maps.

Alternatively, if you have a GPS handheld (e.g. a Garmin eTrex or similar) or phone application (I recommend Maverick – it supports Ordnance Survey Explorer Maps), you can use either this KML file or this GPX file to import the map into your device.

London Brithon Trek 2014 (map detail)