I have done the research and below is a link to read up on it.
http://www.ssa.gov/international/Agreement_Pamphlets/uk.htmlI wrote the HMRC to request the certifiate on continuing liability (which means I wont pay self employment tax or medi/ss to the US)
HMRC sent back a very nice letter stating: Once you are registered as self employed in the UK and taken on work in the UK for at least 4 months send back the application for certificate.
Name of Application: Application for Certificate of Continuing Liability for Reciprocal Agreement countries
Now to wait till August to send all this in but at least I got a response and a good starting point. I foudn this by searching and our friend who is an accountant wasn't sure as its hard to find a UK/US person in such a small village.
Just thought I would post this as genreal knowledge and MY experience.