This guy is fully prepared to drive his van into the side of another road user's car to block a safe and legal traffic merge right by a sign that says, "Merge in turn." This displays the mindset and maturity of a toddler having a temper tantrum. If he has no care for his property or other people's property and thinks he can somehow escape the financial and legal fallout that results from a traffic collision he's caused, he's obviously not going to be careful about the work he does on your house and take responsibility for putting right anything that goes wrong. You're going to be dealing with someone who easily flies into a temper and refuses to accept any blame for what he's done wrong. A one man and his van operation with only a mobile phone number and domestic flat address that's to be avoided.