Hi Anne

I can only speak from my own personal experience... I have found that the midwives are so much more understanding and supportive than my regular GP. I guess it is because this is their job... to be around pregnant mothers and to monitor their pregnancies and their upcoming deliveries.
I only see the one midwife during my visits too... for me, it makes it more personal, as she is going to be there when my baby is born, where my GP won't be... if I have any troubles that really can't wait, then I will see my GP, but I haven't had to since I was 10 weeks pregnant.

I say just do what you feel is best for you... if you feel comfortable with just your midwife, and you are in fine health... why change?
I am sure you will work out the best situation for you.