I guess it is possible to have online medical advice and consultation for Diabetes from a registered doctor . Do you know any doctor or Hospital providing such service?
I understand there are GP services in UK, such as Torq Penderloin describes, however, given its very nature I wouldn't have thought that diabetes lends itself to a completely distance relationship. Aside from anything else whomever you were consulting with would want recent bloods, to assess the "current state of play", and I know of no Doctor who would be willing to have a clinical discussion based upon tests they had not themselves instructed, or at least from a Lab they are familiar with. You could be showing them anything from anyone. And of course, the chronic nature of diabetes means a one-off consultation is unlikely to be completely rewarding.
I don't know where you are, but what is the underlying issue? Do you want a consultation with a Doctor your GP will not refer you to? If that is the case, that's easy to work around, but you need to be very clear in your objective and that it firstly has the potential to better your outcomes, and does not put the professional you consult into a compromised position.