New mount arrived, so set about fitting yesterday to my 2016 Haibike All-Mountain SL. Took about 25 mins and was fairly straight-forward. I attached a wire to the old cable before I puled it out and then used that wire to pull through the new cable - couldn't have been easier. A 15 mile test ride was good and the err15 message did not reappear. Think I will leave the display in situ from now on in the hope that will lessen the wear between the mount and display, as from all I have read this seems to be the cause of this error. Thanks for the tips above as they helped.