Alex – Well done for trying. At least you didn’t miss a positive from your observing site!
I have had two similar experiences; one when a few minutes before the predicted time, a cloud appeared from nowhere in a clear sky and prevented any timing. And another occasion when I had to travel 12 miles to get to my observatory so by the time I got there the sky had started to cloud over badly. I set up and managed to have enough sightings of stars to set up pointing the telescope in the right direction and, low and behold, some minutes before the due time a sucker hole appeared allowing me to achieve a timing.
Richard