Went to Adelaide a few years ago now but had a 2 night stopover in Singapore. It was great, really cheap. I booked via travelmood who were fantastic, gave me lots of options for stopovers and hotels. I called them and they chopped and changed things with no complaints a few times before i booked. I stayed in the Grand Copthorne which was nice and added £68 to my stopover flight bill. Worth giving them a ring to see what they can do for you 08709 903117.