Hi Simon,
If you’re registered on the 6 Month course, then you definitely have access to Level 2 and it should be working in your app,
Are you using the iOS or the Android version?
If it’s iOS, you may find a solution here SSiW iOS app just updated or if not, you can leave a message there and get help with that.
If it’s Android, then this may help you Lessons not downloading on android or leave a message there for our volunteer Android developer.
Dee