[WillPS]

I wonder if Network maybe used a "press on demand" service, due to the niche nature of their products.
There are print-on-demand options available for books so I would be surprised if it wasn't available for disks as well, since most professional disks are stamp based and can be knocked out in bulk through some fancy machine (glass master?)

Amazon do this in the States - the products sent are just burnt DVDs though. Not wonderful from the perspective of a buyer who wants something which will "work forever" since recordable DVDs do not last the same way properly mastered ones do.