Hi Hayley,
My first appointment was with my midwife at my local surgery so it's a bit different to your situation.
The appointment took about an hour. First of all they went through my medical history, they have to fill in lots of paperwork, take copies out to be sent to the hospital of your choice. Not far for your copies to go if the appointment is at the hospital.
She measured my height, weighed me, took my blood pressure, asked me to pee on a stick (showed protein in my urine - bit of a worry), took a huge blood sample. The biggest that you'll have to do is at this appointment. I hate needles.
She gave me loads of leaflets and a book and that was about it. Got my next appointment mid Jan.
You will have all that and your scan in one then - very convenient.