You could look into home based family daycare. I don't know if they have these sorts of programs in Melbourne, but basically the way it works is the carer looks after the children in their home and places are limited to 5 children. All the carers are qualified and have the first aid and get thoroughly checked out. In the town where I live I know of several Mums who work on a system like yours and they all have their regular carers and they just drop them around whenever they work IYKWIM? And the costs are rebatable too.