I have managed to get our GeoNetwork catalogue to harvest from the internal
GeoServer using the following service URL
http://localhost:8080/geoserver/ows?service=wms&version=1.1.1&request=GetCapabilities
The data in GeoServer has been separated by bringing grouped data into the
service through different 'Stores'
The upside is that it the harvest gets everything 
The downside is that the GeoNetwork only allows the data to be categorized
into a single ISO category i.e. Boundaries
Does anyone know if there is a way to use the GetCapabilities function to
extract certain datasets only, maybe by store or some other attribute?
Your assistance, as always, is very much appreciated.
Regards
Dean Howell