If you're talking about a true lightning strike on the supply network, then that's a rather different kettle of fish from the alleged 'surges' against which these devices are claimed to protect. What sort of 'damage to a customer's installation' are you talking about?I fitted a transient voltage surge suppresser (TVSS) into my consumer unit after seeing the damage a lighting strike did to a customers installation who lives a few streets from me. I'm not sure wether it will actually work, and hope I never find out, but it might just make the difference.
Kind Regards, John
Sky box set on fire. Telly written off, RCD exploded that sort of damage! The lightning hit his tv aerial and vaporised the cable into the house!