Thank you for that. In all honesty the US client will pay anything to make this contract work and I'm sure they will in addition, do whatever it takes with the contract.
The problem I am having is so much conflicting information. On the one hand this will be under UK law and taxation, as it is here that I have a permanent residence but on the other hand I will come under US tax laws, etc as it is there that I will ultimately be working.
All very confusing.
M