And here's an excellent tool that lets you do a reverse search back from any location by:


Typing a British or Irish address, post code or place name in the location box;

or

Panning and zooming the key map.


Click here to go to the site

A great tool when filling out those route sheets!

Thanks, Barry. Yes, that's very informative. I had not realised that I also have to pay attention to the underlining underneath the (eg) C3 code, as that indicates the level of minor changes.

This also helps me better understand the OS website. I thought that an edition listed as "C2-" was a typo, but I now realise that the "-" indicates minor revisions to the C2 edition.

All fascinating stuff!