An added piece of learning from all this is that I need to pay closer attention to earnings and ex-div dates. Is there a free site where this can be easily accessed?
7th April was the annual shareholders meeting rather than a formal earnings announcement, although I should have realised that there would be price sensitive info announced. And as the 2 dates shown above (w/c 21st April and 29th April) are both after expiry of the near month short puts, I can't see how this would have helped me.