The same week, Julie gets a call from the Berrytown local council about an upcoming 'Easter Eggs Hunt in the Park' event. Peter from the council tells Julie that they have sourced a range of local businesses to volunteer their services for the event, since it is the annual charity fundraiser, for the community's wildlife sanctuary. "Everyone in the community is pitching in - we just need someone to manage all the traffic on the day! It gets very hectic and we open up part of the local football oval to accommodate all the extra parking." Julie says she is willing to help. "Wonderful!" says Peter. "We don't have much to offer in return - only a small Easter hamper of goods donated by local businesses." "That's fine," replies Julie. The day before the Easter in the Park event, Julie realises she has accidentally double-booked her team. She calls Peter: "I'm so sorry but we won't be able to help with the Easter event tomorrow after all!" "What?" replies Peter. "You can't back out now - we have a binding agreement. You can't simply change your mind!"

answer using IRAC method (Is there a binding agreement between Peter and Julie, for the local fundraiser job? according to Australian law which case law applies ?