Thank you.
Well, it was already off. But turned it on and off again seems to have done *something* at least. I've successfully deleted a film and a couple of full seasons of tv episodes.
But there are still problems with deleting individual TV episodes. Sometimes they simply don't go away when I slide them to the left.
But right now it seems to go OK in Storage Management. Right now I can delete there.
-----
BTW, What is up with this option "show iTunes purchases"? Why would you *not* want to? Also, it says it will only show those which are downloaded, but when I turn it on, it shows *everything* I've ever bought. (At least for the account I'm logged into on iTunes Store, I am in the UK, but for some reason I have to have a US account too, to get The Simpsons.)
Thanks for helping!