Thanks for posting the photos John. Mine has different orifices and chambers, and the plug is in a different position so I don't think the spare you have will fit:

[Linked Image]

Jon - Thanks also.
I've tried the code reader thing and no faults are showing up so part swapping might be the only way. Will have another look at the OBD readout after a long drive tomorrow. I'll also see if I can do some clever number matching on eBay.com or order one from the US if necessary.

Chris