How long does the OSCAR scan roughly take?

Depends on waiting time. I arrived early for appointment at 10.30am, waited till about 11.15am. Scan took about 20-30 mins depending on position of baby. Had to take blood test after scan & was done by 12.15pm.

I just did Oscar test today and it took me about 3 hours, inclusive of waiting and registration time! Not quite sure if it will be the same for you thou!