I'm sure he'll have plenty of questions but it's not the place of a doctor to judge. I doubt he'd wave you away, the NHS GPs are usually very accepting of all concepts and ideas. It's their job to go with the flow of medical discovery, ya get me?
If you're really worried, is there any way you can re-schedule the appointment with your usual lady doctor? I had to go in for some very private things once and they only had a male doctor available, so I rescheduled a few days later to see a female one.
As long as you're not in a hurry, there shouldn't be any problems with rescheduling, right?