"Two test sittings in a six-month period means that the dates of the sittings must not be more than six months apart. For example, if your first test sitting was on 1 March, the second sitting must be no later than
30 August. If you are providing test results from two sittings, you may provide results of any two tests taken within a six-month period as defined.” https://www.nursingmidwiferyboard.gov.au/registration-standards/english-language-skills.aspx