I am planning a homebirth but I still booked into a public hospital - just in case. I booked in when I was around 8 weeks and didn't get my first appointment there until 14 weeks. When you ring they will usually ask how far you are or when you are due and probably give you an appointment subject to this - or availability. You don't need a referal to make phone calls just one to take on you first visit.

Take care
Trish