I have just update the Locate page so this now shows grid-squares at their given precision.  It was difficult to see when, for example, giving a six-figure reference exactly what area this enclosed.

Having done this it is apparent that Google Maps are not like 'normal' OS maps with a rectangular 'metres on the ground' view - they are a more conventional map projection.  Consequently the grid-squares are not actually 'square'!

To see this in action go to ST and this will show the 100km square 'ST'.  Once on the map enter SS (in the search box and click locate).  This is our other 100km square.  It seems that the further east you go (like Norfolk / Suffolk) then the more marked this effect it.

Anyhow, we can now see exactly what area is defined by our grid-references at any precision and I hope this is helpful.

Also worth mentioning is that you can provide a link to any location in the posts here simply by writing [[locate:position]].  For example [[locate:Montacute]] will show as Montacute or [[locate:ST477171]] will show as ST477171.  The 'position' can be any grid-reference or any locatable position.  See the help link at the bottom of the Locate page for more details.

If you notice any strange behaviours with this - or have any ideas for enhancements please let me know (Contacts).