Its a funny one, JW used to call it Porter Malt (Roasted or Dark Malt), I believe it is the malt made for Coopers as if you are talking to anyone from Coopers about their dark beers (Dark Ale and Stout) they always refer to "Roasted or Dark", when I did the tour a couple of years ago, they said the Pale and the Dark ale were the same beer with a 5% of the base malt sub of R or D. Play around with the numbers and it all lines up, as does the flavour.
Personally I think its one of the best Coloured malts made in Australia, good colour, nice roasty flavour without going over the top or tasting burnt...
Always surprises me how little people use, it's great value for money and very good tasting.
Mark