I would get in touch with them, if I were you. They will have a record of your name as having won the crossword. Look for contact details on line. HOpe this is helpful, Chox.
Won the Big Monday erlier this year and the cheque arrived within the week. Having said that, I also won £25 on Skeleton 3 weeks ago and the cheque still hasn't arrived. Have seen post on here before, people complaining how long Express sometimes take to send out the winnings