[Proj] Proj Digest, Vol 95, Issue 19

[Nick Hopton]

> You have to pre-process your grid references in order to get Easting and
> Northing values in metres from the false origin of the grid. The
> 2-letter code "SH" basically means that you have to add 200000 metres to
> your Easting value 12345 and 300000 metres to your Northing value of
> 12456. Once the pre-processing is done, you can use cs2cs as suggested
> above...

The National Grid Reference Converter will batch convert OS grid
references to coordinates:

http://digimap.edina.ac.uk/webhelp/os/data_information/os_data_issues/ng_converter.htm

-- 
Nick Hopton, Caversham, Reading, England.