Hey there Robitsan,
It sounds like you want to download the SD version of your Purchase in iTunes. First go to your download with these instructions:
- Click iTunes Store near the top of the iTunes window.
- Click the Purchased link at the right of the iTunes Store homepage (below Quick Links).
- In the page that appears, select a category.iTunes shows you which of your purchases are available for download. You can view all of your past purchases, or just the ones not currently in your iTunes library. Items already in your library aren’t available for download.If you select Music, you can view your purchases by song, artist, or album. If you’re viewing by album, click an album to see which songs on it are available for downloading.To search for an item, type its name or a keyword in the search field, and then press the Return key to view your search results.
- To download an item, click its Download button .
From: iTunes 11 for Windows: Download previous purchases from the iTunes Store
When you click the Tv Shows or Movie tab, at the bottom right there will be a checkbox that says Download HD when Available when available. Uncheck that and then you will be able to download the SD version of your purchase.
Thank you for using Apple Support Communities.
All the best,