Just thought I would write this as it might be of help to some people.
I spoke to American Express in the UK yesterday as I wanted to give them my new address here in the USA, as I still planned on using it until I got myself a Credit Card here.
They asked me if my move here was permanent and I told them it was. They said that in that case I was eligible to change my UK AMEX card to a US AMEX card. Not only that but they would also report my UK credit history with them, to the Credit Bureau's here. This is great as I always used the card in the UK and therefore have an excellent credit history with them in the UK but I'm starting at zero credit here.
Just wanted to let any other VJs who had an AMEX card in their home countries know this.