Fuji took my X-T1 for repair under warranty. As usual they send their free postage foam padded box. It took just over a week from reporting the issue on the site to receiving the camera back home.
Sadly Fuji have failed to address the reported problem (a row of 4 spots appearing since purchase that refuse to clear even after professional sensor cleaning)
It looks like the Fuji Techs simply performed a Sensor Clean which frankly I am able to manage myself. I am very disappointed. I now have lost a week with my camera and have a sensor that is actually worse than before.
Annoying as the issue is so small that it was almost not worth addressing and now with the failed attempt it won't be worth the hassle as I will have to repeat the return to service exercise.