follow your insurers advice, nothing to worry about. The claim can be made via your insurance, thats why you pay it. Its always worrying when you get a lawyers letter. My daughter had her ceiling come down after her upstairs neighbours washing machine leaked over a long period. water accumulated inbetween two skins and finally flooded through. she gave her neighbour the option to put through insurance or pay the bill. i'm suprised your neighbour didn't offer you an option or enquire about an insurance policy.