My Dad has recently gone through a gas pipe in his garden. It was between 2-4" deep under the ground. With no marker tape it tell him it was there. It was only a puncture. National Grid came out to repair it. No mention of been charged for it. Just now received a bill for £109.29 the letter also states that because they used a mole no need to use marker tape. How does he legal stand and does he have to pay this bill ?