I know this is an old post but I thought it would be nice to update everyone,
@han7681 and myself continued the conversation via private message. After a few months of development on evenings and weekends,
@han7681 is now having a go with the first draft of the software. If anyone else has any small (or large) software projects that they feel would benefit others as well as themselves, feel free to contact me, this isn't a sales pitch as I'm not charging

Also if anyone wants to track Royal Mail (or others) tracking numbers in bulk, let me know and I'll send you the url.
On a different note: if anyone is planning to use the RoyalMail API expect it to be a challenge, the API itself is straightforward and the docs are helpful but access must be provided manually by Royal Mail staff, this lets it down as it was not straightforward.