Spotlight not finding files

I have a problem where Spotlight won't find various files on an external USB drive.

In this shot, folder '2112-Fentons' is visible:




Yet when I search, nothing appears:




Other searches will turn up images but no folders, and vice versa.

I've rebuilt the Spotlight index with onyx, but it makes no difference.

It seems to be able to find recent files since around Christmas no problem.

Once again, I find the solution as soon as I've posted!

Added the drive in 'privacy' under Spotlight prefs and then removed it.