I put in an advertisement in the paper for the sale of some old equipment. A lady came and sighted the goods, and then she asked me to hold the goods for a week while she conversed with others and I agreed. Within 5 days I sold the equipment and rang her to tell her so. She now wants reimbursement for her troubles as she had to get a flight over to see me. Do I need to pay her, or is the advert treated as an invitation to treat under Contact Law?