Ok so for those not on the messenger chat, you will need to book your desert pass online and also your camping, they require you to book a site now so when you have paid online for the pass then book your camping and use the reference number of your pass to get free camping at Dalhousie .
https://www.parks.sa.gov.au/book-and...ert-parks-pass
https://www.parks.sa.gov.au/parks/wi.../booking/73186