I pulled out too. Waited until Friday evening before deciding.
Referring to yesterdays forecast, the thought of getting a soaking in the morning and then, what would feel like, freezing for the rest of the day didn't float my boat. Then I look this morning and the forecast has changed again for a soaking all day!
Really disappointed, but considering doing it as a DIY when the opportunity arises.
Thanks to John of course for organising the event.