【分析解答题】

Ano Ltd is a publisher specialising in producing scientific textbooks.In January 2013, it decided to produce a new edition of a particular book and commissionedBox andCox to produce the work.Box was to provide the text andCox was to produce the extensive diagrams and each of them was to be paid ￡5,000. The contract entered into betweenAno Ltd andBox required the text to be produced by 30April 2013 and the terms ofCox’s contract required the diagrams to be submitted by 30 June 2013.In March 2013,Box informedAno Ltd that he would not supply the finished text on time unlessAno Ltd increased his payment by ￡1,000.Ano Ltd agreed to the increase but whenBox submitted his invoice on delivering the text,Ano Ltd refused to pay the additional amount.In May 2013,Cox informedAno Ltd that he was no longer willing to produce the diagrams for the book.Ano Ltd can get someone else to produce the diagrams, but given the time lost, they will have to pay an additional ￡500 to produce the diagrams on time for printing the textbook as originally planne

D、Required:In the context of the law of contract, advise: (a) what actionBox can take againstAno Ltd to enforce the additional payment; (5 marks)