I had the same OB for both my births and went private.
For 1st he came into hossie to check on me and offered to break my waters which I took up. He then went home (it was a Sunday). The midwife called him back in when I started pushing about 3pm and I had Mason at 4:30.
For 2nd as I went to hossie at nearly midnight the midwife didn't call him till she knew for sure I was going to have baby so Dr didn't have interrupted sleep. She rang him as Angus crowned when the waters broke. I was on all fours on the bed pushing when he came into the room. He had his hair sticking up ****y style!
I had Angus at Berwick and he lives very close to the hossie. Any further and I don't think he would have made it.
If you are concerned about OB attending maybe ask when their holidays are scheduled so that is not a problem.