Now I’m wanting to go back to the UK, I am looking to transfer my IAA license back to UK, and want the rating on the UK license.
I'm pretty sure that you can't do that. The point of the exercise is to keep an EASA licence alive rather than to have a licence that you can actually use. If you are going to work in the UK, then once you start a new type rating, transfer over your IAA licence to the CAA and add the new type rating once you've done it.