Hi Tony

There is a Face to Face Sessions report source that you can use for this in the report builder - not sure when this was added but is on the recent v2 .2.16 .

This include columns for Number of Attendeees and Session Capacity - the available seats can be calculated from this.

You can add a filter search field for the course name which will save with the report see http://help.totaralms.com/Report_Builder.htm for more details on the options you can use.

Craig