[Talk-GB] OS grid positions

[ael]

I have been encouraging a friend to use OSM. He has just mailed in
puzzlement after trying to find an OS grid reference (presumably
looking at mapnik).

I saw http://help.openstreetmap.org/questions/2056/using-the-ordnance-survey-national-grid-with-openstreetmap
but just converting a single grid reference to a good approximation to
(lat,long) isn't *that* difficult, surely? My Garmin does it a less than
a ms or so with very low computing power.

Or am I being naive?

ael