The sleeve with its two clamps to suit years 65/66 is listed as part M3310D (RH or LH) for 6 cyl cars with manual steering.
For new in Melb try East Coast Mustangs in Lilydale, or Mustangs of Melbourne in Kilsyth. Used try Barry at Early Pony Parts near Bendigo, who advertises here.
PS. If you pack out your front number plate with 3/8 tube, a fibre washer and long metal threads, it'll sit nice and flat.