Thanks for your reply. I have a Wi-Fi based OBD device (ELM327) so will see if that works with the FORScan software mentioned. I also have a Opcom but think that is just for Vauxhall (I'm not sure). Will give it a try tomorrow.
One of the sensors was definitely damaged and this was replaced, maybe the replacement was faulty ??
When you mentioned that one sensor faulty and the whole lot shuts down, wouldn't the other working sensors still make the clicking sound ? (Which they didn't) ?
Thanks in advance.