Finally happened to me yesterday too. I really should have followed the prescribed advice and ordered a new key before. At a glance there’s no perceptible change in the key. It hasn’t noticably expanded.
A shame – now that the rain’s stopped I was looking forward to some BB’ing this weekend.
Anyway, a new key is ordered and promised within 3 working days. Am sure it will arrive just as the rain resumes next week.
Long time users – don’t delay: get a new key!