Cool, that looks like a usable solution until they implement something more practical.
Anyone trying this, you have to have Show hidden folders shown in you windows option. This is a fairly new laptop and I hadn't got round to setting that yet.
There seems to be an XML file for each Programme in Command Centre
AD2
Sonar
D-Pro
Rapture
Melodyne
Looking through the States of the various files there are the following options.
HiddenNotInstalled
HiddenInstalled
Installed
NotDownloaded
So in typing this I've actually answered the question I was going to ask. You simply remove the word 'Hidden', not the whole entry for the State so 'HiddenNotInstalled' would become 'NotInstalled'.
Thanks again for the suggestion.