Constantly re-downloading additional content

I have just set up a new Macbook with Garageband and noticed that my old projects sound all wrong, and then realised its a new version to what I had on my previous laptop.

I remembered previously I had downloaded additional free content, so I tried to do that again with GB10, but could only find an option to buy additional content for £2.99. I made the purchase anyway and got the prompt to download a) 150 sounds and 1,500 loops and b) 14 Drummers and their kits. I did this and it completed fine, but the option to "restore purchases" is still clickable in the GB menu, and it happily keeps redownloading all of this content all over again.

What I'd like to know is - does this mean GB still thinks it has content to download (and whether it actually does or not), or whether this option always remains clickable and my expectation that it should grey out is just my incorrect assumption based on what I expect it to do?

Is there a way for me to check if I've got everything? I'm still getting an error that "Live Rock Kit.exs" cannot be found when I load up one of my old projects.