Pegasus R4 refusing to mount on nMP and Mac Mini

Just setting up a nMP that I'd bought a Pegasus R4 for. Mac Pro is great, but the Pegasus R4 doesn't mount. It appears in the System Report as a recognised/named device on the Thunderbolt Bus, but it just doesn't mount/appear on desktop. Promise Utility is installed, and I've run the updater on it, but also doesn't seem to see the drives. I've ran a system re-install (as suggested in this thread : https://discussions.apple.com/thread/5480005?start=0&tstart=0), and it made no difference whatsoever.

I then tried the Pegasus with my late 2012 Mac Mini (that I'd just updated to Mavericks), and it's the same story with it - the drive shows up in System Report, but not in Disk Utility, Promise Utility, and it doesn't mount.

I know there have been sleep/reboot issues with the Pegasus mounting on Mavericks, but has anyone solved this problem?

cheers.