As he has issued the cheque, in law he has admitted liability, keep a copy of all corrospondence between you, its your choice whether you give him time to pay, if it was me i would give him the time but not a day more and add that he should be responsible for getting payment in cash to you before the deadline and that you will add interest on the debt and seek recovery through the county court if he fails to pay on time, or he could return the item, dont accept another cheque though.