So after the last post, I followed up with an email to Google Support and this time there was a response within 30 minutes, with the RMA details as below (full email). Hurrah!
2 days later I got my replacement device. Double hurrah! Backed up and restored data to the new device and on to returning the old device
Packing the device on Friday 29th and re-reading these directions, I realised that I didn’t get any confirmation email nor shipping labels. Cue a another call to Google support and Google Support lady (first one I’ve spoke to, previous 2/3 calls have all been guys) says that they don’t email shipping labels to Australia and that the courier man should have it.
Courier man never came yesterday, so retried requesting another return request today and got a “Collection for given RMA Number has already been requested”. So yet another Google Support call….
The Wheat Field 
same for me