Just having another look at the video...
I'm wondering if the first point of impact was the MR making contact with the lamp-post. And if the hole was taken out of the building's wooden cladding by the tail as the aircraft was suddenly rotated.
Have a look at the marks on the lamp-post (roughly in line with the middle of the open window in this photo). Having watched the video a couple more times, it seems this way, but perhaps my imagination.
