Tamaris, I don't know if you've ever gone private, I haven't, but I believe you pay for the Consultants' time, so 15 mins might cost you £75 and obviously more the longer you are with him.
Hopefully though, he won't refer you to a psychiatrist or tell you you have S.A.D.
As I said earlier, I would consider going private if my GP tells me my thyroid is fine and there's nothing wrong with me.
Also, I would pay to have more than 15 mins, as I don't believe that is enough time to talk about it.