Advice about seeing my GP and starting transitioning (UK).

Hi Ellie here, long term lurker first time poster, so I'm a 17 year old transgirl living in rural Wiltshire in England and I'm looking for some advice.

I have only come out as trans to a few friends but I've started to feminize myself over the last few months; shaving, tucking, women's clothes, self voice training and wearing make-up. But I want to go to the next step getting HRT and I know this process will take a long time on the NHS so I want to start as soon as possible. Now for the questions (sorry about the wall):

1) Do I just phone up my clinic and say I want to see my GP about Gender Dysphoria? or do I ask about transitioning, what should I literally say when booking my appointment?

2) I am going to bring a copy of the latest NHS Interim Gender Dysphoria Protocol and Service Guideline 2013/14 with me. Is there anything else I should bring?

3) I hoping that by at least seeing my GP this will be convincing enough for my parents to believe I am Trans when I come out to them. But would you recommend I come out to them before seeing my GP? I am worried about their reaction as my mum said she wouldn't know what to do if I was trans (well she said Ladyboy) but I think shes starting to suspect that it's more than a gay thing with all the stuff I said above.

Thank you for taking the time to read this, and a massive thank you to /r/asktransgender you have been so helpful to me this past year.