Hi Andrew the customer has every right to claim for damages from you. He can only claim from you and not the third party. You then would claim your losses from the third party.

I would give the third party every option to put things right first, if they refuse I would foot the bill to make good for the customer and your reputation. This would then get the customer out of the equation with no love lost.

I would then start a case in the small claims court. If you went through your insurers the matter will take months to sort out and your customer won't be very happy waiting.

Keith