When we moved to the
UK 5 years ago, I just walked into my nearest GP surgery and registered. I did not have to provide any documentation other than proof of address that I lived in the catchman area, and my VISA that proved I wasn't illegal. I was given an NHS no. entitling me to all care as per a UK resident.
The rules may have changed but in my experience of working for the NHS it is individuals who are here 'illegally' that have to pay for treatment.
Good luck with the move over!