John Smith and Peter Brown have a contract for the sale and purchase of a car. The purchase price which Peter must pay is $5,000.According to the agreement, John agrees to deliver the car to Peter, and Peter agrees to pay for it two weeks later.After Peter has taken possession of the car, he calls John and informs him he is unexpectedly short of money and cannot pay the full $5,000. He asks John whether he would now accept $4,000. John considers this request and decides that, in the circumstances, he is better off taking $4,000. John informs Peter that he agrees to his proposal. Peter pays John the $4,000 on time. A week later, Peter inherits $15,000 from his uncle, and John hears about Peter's inheritance through the grapevine. He demands that Peter pay him the $1,000 balance owing.

Required

Referring to relevant principles of the law of contractual consideration, advise Peter whether he must pay John the $1,000. (New Zealand legislation)