Hi Mick,

The following sites may be helpful for identification:

Bill's Banjos

Mugwumps

There are several factors important in lowering/setting the action of a banjo. These include neck angle, skin tension and bridge and nut height. Rather than explain in a long post here, most of what you would need to know is on:

Frank Ford's Frets.Com site

Just scroll down to the banjo section!

All the best!

Peace,

moo