如下时官网内容:
If you are applying in Phase 2, you will be applying using our enhanced Immigration Online system. This means you will be able to apply even if you have not been able to get a medical certificate before you start your application. If a medical certificate is required, you will be asked to provide one later. If you have been able to get a medical certificate before you start, INZ will have this information and you will not need to supply another one.