On the phone, all media shows as expected in associated apps, root explorer sees all files.
The problem for me appears to be on my external sd card (its a Samsung 64Gb, formatted to exFat)
I was wondering if there is a way to force a refresh on the PC side?
Barring that, I think the only option I have is to back up the card and re-format it.(which will take me a couple of hours!)