I know here in tassie if you dont have rego sticker on then you cant drive it, unless you are going to get the sticker or a pitpass in order to get your rego. but just to take the car home or something would be a ticketable offence.
That said if you got the car yard to put what your last post said in writing and got them to sign it then if you did get pulled up just show em that. However i would not be driving it more than that until you get the sticker.