Some positive news to report as Bosch has now agreed to supply a changeover replacement Nyon under service/warranty/crash replacement. This somewhat restores my faith in Bosch, pretty important as we have a Bosch induction cooktop, wall oven, washing machine, power tools and garden equipment. I swapped the Nyon from my Delite to my Roadster as a temporary fix and interestingly the Nyon from the Delite registered the distance travelled by the Roadster so it seems some info is stored by the motor electronics as distinct from the Nyon. I guess I will confirm this when I fit the replacement Nyon.