ooh that sounds a little unusal, I guess avery area is different, in our area in berkshire, you have to see the doctor first about 8 weeks onwards and then after they make the appointment for the midwife booking in for after 10 weeks, onwards who would sort out the 12 week dating scan I believe.
You might want to ring your doctors and just check with them, just incase appointment has slipped through the net.
I would think they would need your notes for when you go to the scan. Just an idea, hope the details arive soon for you.