|Disney's Brave; HD vs SD File Sizes|
As you'll know to download your pre-purchased content you need to go into the iTunes Application your iPad and then touch on the "Purchased" button (bottom right);
|iCloud Purchases Tab (iTunes on an iPad)|
|Downloading an iCloud Purchase Direct to an iPad|
Occasionally you'll notice that instead of the "Cloud" icon you'll just get a "Watch" button. I'm not entirely sure what this button is for - it doesn't seem to actually start the movie playing (at least it doesn't on my iPad 2 or my iPhone 5!).
The problem is you can't choose between SD and HD when you trigger the download.
There doesn't seem to be any quick and easy way around this *however* there is a long and complicated way - go back into the iTunes application and search for the video you are interested in and go to the page. Taking "Final Fantasy: The Spirits Within" (as shown above) when you open the films page in the store you get the same iCloud download icon but this time you get the HD/SD option for your iCloud download;
|iTunes Store Movie Details - With HD/SD iCloud Option|