C# Postcode Distance Calculator

I require a C# class written for me that uses the Google Maps API to give me the following information: * Distance between two UK postcodes, I want the full postcode to be used so that the distance is as accurate as it can be * An option to specify "as the crow flies" or "Road" distance * An option to specify the measurement, kilometers or miles * Performance is key as my website will be making multiple calls to the API; my website displays a list of products and needs to tell the user how far away from the product they are, this is in the form of a list The class should be self contained with public function for me to specify my options and postcodes, i.e. a procedure call of: [login to view URL]( PostcodeA, PostcodeB, [login to view URL], [login to view URL]) Where: PostcodeA is the source postcode PostcodeB is the destination postcode [login to view URL] is the measurement [login to view URL] is the distance type ## Deliverables This C# Class will be incorporated into an existing website; the successful buyer will only need to provide a test harness that I can use to validate the functionality works. Another development team will be responsible for incorporating this functionality into the core website. Testing will be performed against the Google Maps site to ensure accuarcy of distances; a tolerance of 5% within the distance will be allow depending on how far the postcodes are, i.e. a 0.7 mile journey being represented as 0.6 is fine but 0.1, 0.2 will not be accepted.