Congrats MrsC - Sounds like you're getting organised. I'm not going with an OB just my GP. I have to see her every 4 weeks until 28th week then every two weeks so I think that at 7 weeks that should be fine. Since I found out I was pregnant at 3 weeks I had all my bloods done at 5 weeks but my previous pregnancies the tests were done around 6 or 7 weeks so not to worry. I haven't had a dating scan and am unlikely to have the NT scan. A lot of the women I've seen who have dating scans or multiple scans are those who were not regular, are unsure of dates or high risk, recent m/c or bleeding. They generally don't book you into the hospital until 12 weeks.
Have a wonderful pregnancy and take care.