Hello again. I’ve solved the demo issue and indeed it is that you need to have updated the Kontakt 6 library. It costs £89 from Native instruments to update.
It is a little misleading as NI added an update to Native Access for Kontakt 6, so I think a lot of people have presumed (myself included) that as owners of Kontakt 5 that they were automatically updated to Kontakt 6 … This certainly seems to be the case on the forums I researched re this issue.
The best way to check is to go to your Native Access app and check your Kontakt instrument. If it says ‘Full Version’ then you are good to go. If it says ‘Player’ then you need to update via the NI web site.
Apologies for the confusion and hope this helps anyone who is struggling.