Thanks for all the replies,
We do live near the sea alright (within a half mile), but my car is fine and all our immediate neighbours.
As regards the angle grinder - a panel beater friend of my husband suggested that could be the problem. Our next door neigbour does alot of work in his garage and driveway. My OH asked him last night and he said he's never used an angle grinder. He tends to tell us if he's doing any work so we can move our cars - he's a very honest guy.
It really is a mystery - a lovely car ruined.
Maggs