Hi Simon,
I'm using now meshlab (
http://meshlab.sourceforge.net/) for cleaning of STL data and development version of rhino3d osx (
http://www.irhino3d.com) for orientation of math data.
As soon as i've done with all corrections, i'll use CATIA for class A surface work and 5 axis CNC milling of model.
Regards,
Ozgur