Finally got hold of them at Outback Caravan Park yesterday (phone: 08 8962 2459). There is currently plenty of accommodation available, rates as follows:
Cabins
Deluxe 2br cabin, sleeps up to 6 (king bed plus 2 x double bunks) $149 per night for 2 adults, additional $25 per night per extra adult (or $15 extra without linen)
"One and a half", sleeps up to 4 (king bed plus 1 x double bunk) $139 per night, extras as above
Deluxe cabin, sleeps 2 (king bed) $149
Standard cabin, sleeps 4 (double bed plus 1 x double bunk) $99 per night, extras as above
Single ensuite room (single bed) $89 per night
Powered sites
$25 for one person
$38 for two people
Unpowered sites
$15 for one person
$30 for 2 people