Doctorates from British universities can be awarded in two ways, either a thesis and a viva examination or (occasionally) by the submission of a body of published work followed by the viva. Arguably Martin's vast body of published work (i.e. his recordings and their erudite sleeve notes)could be sumitted (as if he'd want to!) to a university for consideration for a Ph.D. Newcastle, perhaps?

Guest Pleb - technically the person you visit when you're feeling unwell is not a doctor, but a medical practitioner. Their title of 'Doctor' is a courtesy, just like the 'Captains' of merchant navy vessels who are, of course, 'Masters.' Given the universal usage of the word 'Doctor' for medical practitioners, it will never change but people with Ph.Ds are the 'real' doctors.