I knew something like this would happen with this buyer - bit of a long story, but she now says the item hasn't arrived after I sent it last Thursday 1st class and have proof of postage. She has now asked for a refund, but the Royal Mail won't recognise something as lost until 15 working days after posting.
It's only £7.50, but I really don't see why she shouldn't wait the 15 days as I won't be able to make a claim until after then - plus I'm damned sure that she won't return the item when/if it turns up.
What would you do?