HELP with setting up zones for flat rate shipping

Hi
After getting myself into a mess trying to set up a complicated shipping system I have decided to give up and use the far simpler flat rate shipping costs.

I have loaded in the Royal Mail add-on (just so you know what files I now have cluttering up my modules)!

by following another post I have managed to set up 3 different Flat Rate options but am struggling with where and how to set up the country zones.

I am looking for:

Flatuk - Flat rate for Mainland UK - £2.99

Flateurope - Flat rate for Europe - £8.99

Flatrestofworld - Flat rate for Rest of World - £17.50

I have sorted out the country codes for each zone but am unsure where/how to set them up to work on the flat rate system.

Can anyone help me out?