Almost forgot about this one. The solution turned out to be simpler than I could have hoped for.
- In the QMC, go to the System tab -> Licenses subtab -> select QlikView Server from the list -> Client Access Licenses (CALs) tab (right side of screen) -> Limitations subtab.
- Select "Limit number of CALs"
- Set "Named user CALs" to 0.
- Click Apply. All of the current CAL info will be deleted.
- Set Named User CALs" back to its original value (or however many of those you want to use), click Apply again to activate.
- Go back to the General tab and switch from "Machine name" to "User name", click Apply.
- Go to the "Assigned CALs" tab and add all of your named users and click Apply again.
No quarantine, no waiting, no muss, no fuss. OK - I fussed about having to manually add 53 named users, but that was just me!
Hope this helps someone else,