strange one that will be ( lost card day before and £500 missing ) reported it the next day,
solo card is for a current account and mostly limited to cash machine withdrawal of £250/300 in any one day unless the amount of £500 was agreed beforehand so that makes it unlikely it was from a cash machine,
as its chip and pin all shops have to use the PIN number for transactions with that little keypad thingy so if that shop used a signature then you should be covered and im sure the bank will do everything it can to help you and themselves