Rummaging around on the OS website I came across a useful application for anybody researching a route.

It is called "Where's the Path" and has two panes that displays an an OS map alongside the corresponding element of a Google map switchable between the terrain, satellite image and hybrid modes.

You can therefore compare the OS cartography(Rights of Way, district boundaries, etc) with the physical features.

To find it go to the OS home page, click on experiment with openspace then go to Gallery and scroll down amongst the various applications to find "Where's the path?".