I would take a look at the following article on downloading past purchases in iTunes.
Thanks for using the Apple Support Communities.
I tried what you suggested above, but it doesn't work.
I bought a season on iTunes through my iPad and downloaded everything to my iPad.
I then opened iTunes v. 126.96.36.199 on my Windows 7 PC and went to
first: Store -> Purchased
the show was not visible in either location.
I verified under Edit->Preferences->Store that "Show iTunes in the Cloud purchases" was ticked.
I am connected to the internet.
I had the same problem. Not sure if you've already tried this, but I just went to the iTunes Store, clicked on Purchased under the Quick Links, went to the TV Shows tab, selected the shows and clicked the download icon. The shows now appear in the TV Shows folder in my Library.
Hope that helps.