On occasions the camera would work fine, on other occasions the fault occurred during shooting or as soon as the camera was switched on. Switching the camera off and back on again would sometimes clear the problem and sometimes not!
Time to send it off to Fuji Australia service department, especially as it was still well within the 12 month warranty period. I have nothing but praise for the response and turnaround of the investigation and repair from Fuji. I sent the camera via Australia Post and the next day I received an email acknowledgement from Fuji that they had received it for repair and that their current turnaround is approxiametly two weeks.
After seven days without the camera, it arrived in the post fixed, tested and cleaned. A replacement PWB was required to remedy the fault and now all is good. Great work Fuji Australia, Thank you for the speedy response and return of my much loved XT1.