OET--L, R, W & S, all 4 has to be B or above. They are rated respectively using the letters: A, B, C & D, with A the best! I am not sure if there is such a process as remarking when somebody is not happy with their mark.
All the material is clinically related stuff! It will feel comfortable for people who have medical or nursing background!
I have no idea how it works in marking system when it comes to nurse immigration category. IELTS 7 x 4 or OET B x 4 will be a must for nurse registration requirement, only meeting this requirement can a registered nurse get an employment with a hospital. Then, he/she can be nominated for an employer-sponsored immigrate.
But don't quote me on the current policy on an independent-skilled immigration for nurses! All I am sure is that getting a registration is the essential step even before we can talk about anything else!