Why are the tests and re-sits only available in a scheduled window?

Because of robust governance and checks around the test and who is undertaking it, it is only available over strict and monitored timescales. There will be four scheduled windows each year, one each quarter, for you to select. If you need to re-sit the test, this must be done within the same window as your original test. Your chosen training provider will be able to advise on which dates they are running the test.