Required fields to submit a referral:
      - body_part_ids, modality, referral_information
    Once the referral has been submitted, the patient will receive an email with
    a link to: select their desired imaging centre and request date/time for the scan;
    answer safety question; and confirm the scan.
    If you want to do all this yourself via the API, do not use this endpoint.
    but the "Confirm a referral" endpoint when the referral is ready.