Following his unsuccessful attempt at running an online business, Ruawai Maaka decides to sell his collectables business. Inspired by her poor experience as a customer, and wanting to make a positive impact as the new business owner, Karen O'Leary indicates to Ruawai that she is interested in purchasing the business. Ruawai and Karen swap email addresses, and tell each other that they will communicate by email (using those addresses) to negotiate the sale. Karen emails Ruawai on 15 March 2022, offering $270,000 to purchase the business. Ruawai reads Karen's email, and then replies, stating that he would only accept $295,000. After Ruawai sends that email, but before Karen reads it, Ruawai sends another email stating that he is actually willing to accept $270,000, and that he considers 'the deal is now done'. When Karen reads her emails later that day, she starts from the top of her inbox and moves downwards. This means that she sees Ruawai's purported acceptance email first, and then later sees his counter-offer email.

At this point in time, have Ruawai and Karen formed a valid agreement for the sale of Ruawai's business, according to the law of contract? Please refer to any relevant legal cases and/or legislation to support your arguments