I can’t import the package through Asset Store, I just keep getting this:
I’ve tried closing/quitting absolutely everything else running. If I force quit and reopen Unity this comes back up again. If I delete the Headers file then the Modules folder will come up instead.
Tried checking the permissions on the files and can’t see anything out of the ordinary
Yes, we have already reported this internally (caused by some late changes to package manager), and we do have a fix incoming for Unity 2018.1. I’ll follow up today, and provide more information. For now, you should just use the built-in version of Ads SDK with Unity 2018.1, if possible.