Thanks Andy.
I listened and the clicking was heard from them all fairly loudly (from about 6 inches away) with the exception of the driver outside one which was faint and you needed to be right up to it, but it was still audible. The clicking sounds like an electricity 'spark'?
I found the module where the spare wheel was and reseated the plugs. No change. Still a loud long beep when I put the ignition on or when it goes into reverse.
Suggestions??!