tobo1ie - I agree with Russ, thing is it would be hard to advise anyone on which clinic or consultant is best because we all have different expectations. I could recommen my consultant to you yet if you were to consult with her you might end up thinking she is the worst ever or something along those lines.
I understand your concern though, unfortunately you have some complications there. I suggest you google NHS diabetes clinics and see what comes up, then you could maybe email any departments with some of your queries and see what response you get.
For example I did a quick search on google, one of the first that came up was this one
http://www.bartsandthelondon.nhs.uk/our ... s-service/, best search for clinics this way, maybe the bigger the hospitals the more chance you have of research units attached to them too?
Search for a list of hospitals in the area that you consider moving to, then contact departments for further info/
I have done something similar for a skin condition, I ended up travelling to Liverpool, my GP arranged a referral for me at the time, it worked out for me, hopefully you find what you need in relation to your diabetes. ask around.
All the best to you and yours