I've added the module and it's working properly for a single zone (UK). My client also wants rates for other countries. Looking at the code, it seems this can be done by defining zones and adding tax rates - would this be correct?
The alternative appears to be to create a module for each zone defined so there is an Individual Product Shipping - Zone 2, Individual Product Shipping - Zone 3 etc etc. I'm not entirely certain of how to do this, and if, as I suspect, my client has individual prices for countries, it's going to be rather messy.
Has anyone done this or is there an alternative solution? Do I have to write an alternative solution?