iPhone to PC iTunes U Sync issues

My iPhone 5 contains aprx 40 ITunes U courses that I follow. My pc only shows 5.

All the sync options have been checked and I have no issues in general with syncing to my pc (music ,aps etc all work fine).

I have tried 'transfer all purchases' - no joy

I have tried loggin out and back in - no joy

I have de authorized and re authorized - no joy

ideas please its driving me crazy

Matt :-)