So what we know so far (won't use the word facts yet) The aircraft took off at night from a confined site/HP, the lone tallest tree within a few hundred metres of the site was chopped in half at a point just above the surrounding trees. The aircraft then contacted the ground in the field beyond and struck a substatial row of hay bales before coming to rest in the opposite direction. The crew knew this site well and recently.
We don't know if there was mechanical failure during or shortly after take-off, we know the weather visibility was poor in places in the area, but not what it was like at the site until witnesses/cctv at the house are questioned. Others have speculated that the owner was a man who liked to go when he said it was time to go, but that he felt concerned enough about the aircraft to take procedings against the manufacturer to get rid of it. If it's not mechanical failure, or crew error, it could just be that they were unlucky with the one tall tree in the darkness.