Batch conversion of full UK postal addresses to longitude / latitude

We require a solution that will allow us to import bulk UK addresses to generate their longitude/ latitude, easting and northing co-ordinates. It is important that the co-ordinates represent the location of each property as accurately as possible and not just the centre of the postcode area. The following links show what we are roughly looking for in a solution. The actual mapping of results are not required. [login to view URL] [login to view URL] The solution will allow us to import addresses from an excel spreadsheet and also us to export the results in the same way.