The moment the hammer falls on the auction on your house, you have entered into a legally binding contract with the buyer. They will be required to pay 10% of the sale price before leaving the auction house, if they don’t; you are eligible to sue them. They will be required to pay the remaining balance within 28 days; otherwise, again, you can sue them. When the auction is complete, your solicitor will handle the commission and auction fees/expenses, your outstanding mortgage debt, and obviously there own fees.