Quick answer
For internationally trained practitioner psychologists, Grade B (350) in each of the four OET sub-tests is accepted by HCPC (UK, registered as Practitioner Psychologist) and the Psychology Board of Australia (AHPRA). AHPRA lowered its OET Writing minimum from B to C+ on 18 March 2025 for the National Boards it lists; confirm the Psychology Board of Australia's current Writing minimum on its page. The Writing sub-test is a single letter, usually an assessment or referral. Most marks are lost on Genre & Style: test names and diagnostic terms left in for a reader who cannot interpret them.