This unit looks very similar to one I saw on Aussie ebay a while ago....not sure about the model number. Chances are these (...or a variation of them) were sold down here as well, but may have been marketed under the "National Panasonic" brand name.
it looks a lot like the SS-7700CU and the amplifier in the SS-1100D system (240v 50hz) and the Japan model SC-8400DX (100v 50hz).
Do you have the schematics?
Thanks