Hi there, Chris.  Firstly, you ask where the second volume of
the Audsley book, "The Art of Organ Building", can be bought.
It is available from Amazon.co.uk :
http://www.amazon.co.uk/exec/obidos/search-handle-form/026-0125366-6025257 

I don't know if you are aware that there is a considerable amount
of information available covering the construction of a Wurlitzer 105.
I have been researching this organ for some time and can provide sources
if you are interested. There is also a web site dedicated to the
Wurlitzer 105.

All the best,
David Allinson
Barcelona