Thanks guys! We're off to Bunnings tomorrow to get started on materials, picking up a borrowed nail gun and speaking to the plumber again on Friday to iron out details. That darkroom door is like our prized possession now - The University of South Australia were about to throw it out and we happened across it just in time, I think we paid $30 for it in the end. It's a monstrous thing but you can fit ten people in it at a squeeze.