If this is related to the Google Maps Geocode call try formatting your search string as PostCode + ", UK"
i.e."TN13 2TB, UK"
Another technique is to call "Google local search", see the example
Set the search type to "The GeoWeb" and type postcode as above(TN13 2TB, UK), the source code is supplied.
this looks very helpful, thanks for the link. In the process of researching last night I found out that UK postcodes are the subject of some quite strict conditions by Royal Mail - see
for some discussion.
just to confirm this works fine. I am currently using the UMapper API to allow the user to select the map style they want, and now (thanks to your suggestion) the Google postcode -> lat/long lookup. UMapper already has a route-finder algorithm based on lat/long endpoints so that should be an easy last stage.