Many thanks once again for your advice. the other post suggested checking for moths, whilst i was worried about mice as my wife's Astra had mice nesting in it, I am not aware of any on the Disco. However my neighbour has a bamboo plant that has been heavy with snow and it is has been baning against the disco in windy weather. It only has happened in the drive so will check that out first, thereafter to the computer.
Kindest regards.