I experienced the same unsettled weather in Petra, Lesvos on October 1 (but no mini tornado), which was apparently Greecewide. Someone told me it was the remains of Hurricane Rita.
Incidently, that holiday provided an extreme example of packaged holidays being cheaper than booking independently. I was there for 3 weeks (singly) and the room rates were a mix of €35 for the days in September and €30 for those in October. Convert to £, add £175 for the airfare and £50 for the transfers makes £730. I paid £256 (Manos) and before someone says I must have got a bargain at the last minute, I booked over a year before travelling.
While there I met someone who was in Plakias in May, staying at the Lamon Hotel with Kosmar and gave an extremely bad report of their room and the hotel in general.
Mike