Thanks so much for your reply. It's really worrying that this seems to be a 'thing' with doctors at the moment. I'm really quite worried. The long-term effects of PA can be really serious if you don't have the injections and I don't know what I'll do if they refuse to let me have them.
I'm going to have the (arguably pointless) blood test, but when I go in to discuss it, I'll make the appointment with a different doctor. Maybe another one will listen to reason.