I would modify a Rover blade plate to fit ,as the original blade plates would be hardened and you have a dish( recess) standard.
The 4 mm plate may prematurely wear the bearings out with the extra weight but you could counter sink the centre bolts so would be an option but if you can buy an original it's going to save some work.
If MF will box up a few parts ,Norm can book a courier for pick up ,pack and send can be booked online and they don't charge any more to pick up from your door. The courier price will usually be a little less than Aus Post ,the 2 blade carriers will probably cost about $40. to book the courier.The Only problem is you need a printer to print the Consignment Note.
Not sure what the weight would total but another option is Aus Post and you don't need a printer.
