Well, it was just a bloke falling off a roof after all. There simply has to be a twist. I reckon that one of the two Pargetter brats overheard David challenging Nige as to whether he was a man or a mouse, when the latter had been showing signs of demurring over the impending fateful roof adventure. This will be blurted out at the post-funereal weepie time, and a shocked and bitter Lizzie will make guilt-ridden Dave's life hell for years to come as a result. In fact, she may even try to kill him in about 2017. Tractors make effective lethal weapons, apparently. That will leave the way open for herdsman Sam to renew his bid for Ruth. God, why don't these people just employ me and have done with it.