Complex sentence: During this segment, several fan blades were broken off Clarkson's engine fan, which led to him cutting holes in the bonnet for additional ventilation when they camped; this unfortunately resulted in the roof of Hammond's Toyota catching fire.
Split into simpler sentences: During this segment, several fan blades were broken off Clarkson's engine fan, later leading to him cutting holes in the bonnet for additional ventilation. This unfortunately resulted in the roof of Hammond's Toyota catching fire.