Show HN: Postage Cost Calculator (UK)

This is related to an Ask HN I posted (https://news.ycombinator.com/item?id=8464118) - to summarise, I'm a primarily C# dev working on extending/customising existing off-the-shelf CRM systems, but I want to expand myself and learn more diverse technologies.

I built this as I sell on eBay infrequently, and the Royal Mail price-finder (http://www.royalmail.com/price-finder) assumes you know off the top of your head whether what your sending is a small parcel, medium parcel, large letter etc. so this way you just enter the dimensions/weight and it works out what the different services would cost (and automatically excludes services which aren't available for the dimensions/weight of your package)

I put this together over about a day to start to learn AngularJS (it seemed to have the lowest barrier to entry and my JavaScript skills in general are novice level) - the next step for me now I have something that _actually_ works is to learn how I should re-factor it to make it more maintainable and implement testing of it, so that when the prices update I can be sure I've not broken something.

If anyone has any feedback as to how/where/what I should be looking at doing with it to refactor it to be more maintainable/testable that would be greatly appreciated.

Lastly, all the data it needs is currently stored in the controller (such as the points for different parcel sizes and postage costs) as I was hoping to make it available offline and potentially package it in something like PhoneGap and have it able to run even if there was no network available.