24 hours ago, in the Default Collection Option Set, i configured ZAM to
pick up font files (.ttf, .otf and .fon files).

To configure this, I added them to the 'Addtional Extensions' field on
the 'Collector' tab. I separated them with semi-colons.

ie 'ttf; otf; fon'

However, having resarted the Inventory Process and rescanned a dozen or so
machines, no data is showing up for these file extensions.

For reference, 'mp3' had already been entered in this field, and mp3 files
are being reported back to us successfully, so the exact contents of
the 'Additional Extensions' field are is as follows: 'mp3; ttf; otf; fon'

Is there anything else I need to do to invoke the reporting against these
font file types? Or could I have done anything wrong?

Any advice appreciated.