The Hayden family is close-knit. Dad, Mick, an accountant, and Mum, Joyce, a nurse. The children, Kurt and Michelle are aged 21 and 20 respectively. Kurt is a final year accounting student at La Trobe University, Michelle a 3rd year nursing student also at La Trobe University. Mick has put his 2017 BMW up for sale and has been negotiating sale with a close associate, John, for the price of $19,000. John is interested in buying the car and has informed Mick of his intention to buy the car. On 10 June 2020, John attends Mick's home to inspect the car. Upon inspection, John asks Mick whether he would be prepared to change the upholstery in the car before the sale to which Mick replies: 'That would not be a problem, but the price of the car would increase to $22,000'. John says nothing. Mick proceeds to change the upholstery as requested by John. Mick informs John 4 weeks later that the car is ready for pick-up and that John should issue a cheque for the sale price. John informs Mick he is no longer interested in the car. On 10 July, Kurt and Michelle, in preparation for their friend's wedding ceremony on 20 July, take 2 suede jackets to their local dry-cleaner, Fab Kleen. On arriving at the shop, the shopkeeper tells them 'Today is Fab Kleen special day', and that as such the cost of dry-cleaning 2 suede jackets is $100. The shopkeeper also informs them that because of the increase in demand, the shop would not be able to meet the usual threeday return and that the clothes would only be ready in a few more days after the usual three days. Kurt and Michelle pay $100 and leave their jackets for dry-cleaning. On 17 July, Kurt and Michelle attend Fab Kleen and are told the jackets are not ready. Kurt and Michelle tell the shopkeeper the jackets are needed on the 20th and that they would like to pick-up latest by the 19th. On 19 July, Kurt and Michelle attend the shop but the jackets are still not ready. They tell the shopkeeper clothes are usually ready in three days and that Fab Kleen is in breach of contract. ANSWER ALL QUESTIONS

1. As between Mick and John, is there a valid offer? If yes, who made the offer?

2. As between Mick and John, is there a valid acceptance? If yes, who was the acceptance by?

3. Can John be estopped from denying his promise to buy Mick's car?

4. Are the terms in relation to pick-up date sufficiently certain, so as to enable Kurt and Michelle to bring an action for breach of contract against Fab Kleen?