Sorry to hear about your annoying issue Nick and yours Peter. I don’t know if this might help or not but it might be worth making and breaking the Caerbont ‘Multi Function Unit’ connectors a few times. The + 4’s Ford Visteon EEC-V ecu may be sharing instrumentation data with the MFU over the ecu’s J1850 bus before it gets to the dash pcb (do you still have a MFU Peter?). On later + 4’s the MFU is located next to the ecu in the metal enclosure in the engine bay. I think one of
Dave's old pics of Bumble shows water staining in the enclosure, not so good if the signal connectors are not environmentally sealed.