Thanks Luis . . . whatever the cause, everything is now OK and both the camera symbols and proxy messages have gone.
The 4K test has been completed successfully. There are 8 tracks of video . . . the bottom 2 being a Testcard background with me green screened above it and "colour corrected". The 6 tracks above them are 4K used as PIP and also colour corrected . . . or should I say "colour altered hideously"!
The whole caboodle is 7 minutes long and playback of the unrendered footage is silky smooth in spite of having 8 other apps including DV Resolve open at the same time.
I find 8 GB RAM adequate for my humble needs and the mini is booted from a cheap Crucial 1 TB SSD.
