Changing payments from one country currency to another

I set up an account in New Zealand for Muse and the photographic package in order to provide a website for a friend.  It was paid locally in NZ currency.

I am now back in the UK and would like to pay in Pounds and be able to use everything I have in Cloud here.

The technician has advised that I have to set up a new UK account with a new email address and cancel the NZ subscription set up under the old email address - an address I still use and have done so for many years. 

I have been advised that if I do this, I can still have access to my files in Cloud. I don't see how that is possible given it was set up with different information?  If I need to work on the website I created in Muse, how do I get that information back as I can't see anything that would move one account from the other?  Have I missed something here as I can see no linkage?  Please advise.