Got the letter back today, I still don't have a medical, but I do have what is called here a 'Recreational Aviation Medical Practitioner's Certificate', which will allow me to fly a Cozy with some restrictions. CASA are still threatening to cancel my proper medical, but haven't yet. With this positive news the building switch is going back on.
Problem now is I have no fibreglass, and lots of nick-nacks required (with big price tags) to finish Chapter 9 and move on.
I was going to delay the purchase of brakes & wheels, but had contact with a builder with excess materials he'd like to sell after buying another. Will go and have a look.