On second thoughts it is more than probable the answer given by Marcus is the correct one. The question setter had the answer in a sealed envelope and could be fairly confident that no one would get it right....what are the odds of "guessing" 5423? (Don't answer that).
As for what to do next, I am off to practice my spilling, Puzzle is spelt le and not el. Good jib I heven't mode any other spilling mistales. !!!