Was in the same situation last week - booked a prepaid rate for $99 on needitnow.com.au rather than shell out the $160 the Parmelia was asking, which I guess you have to do as a prelude to the BRG.
Needitnow had a slightly different description of the room as I recall, after reading this thread doubtless the Hilton sleazeballs would seize on that.
OT: Dont use lastminute or wotif any more. IMO since wotif took over lastminute they've become too big, most of the deals have gone and it's just another list of rack rates. Whereas expedia.com.au always has something at a good price, or for last minute stuff needitnow.com.au has the occasional zinger.