I googled my problem and found this page on the forums: Can't load VST Sound Loop Set - #4 by monkeyfuzz - Virtual Effects and Add-ons - Steinberg Forums. So I looked in the media bay after a period of about 24 hours and lo and behold, the two loop sets were showing in the media bay locations.
Does Cubase need time to scan the hard drive to find media, or something? I haven’t done anything to try and find the loops in the interim… Bizarre.
Thanks for your help 