After raising to support tickets and getting the same incorrect response from both of them I finally figured out how to get a power and therefore speed output.
Sensors I use in addition to the Elite Misurio B+ are a Garmin GSC10 speed/cadence sensor and a Garmin HRM
You have to follow the instructions from Elite and set the sensor to 12 flashes (for the turbo muin, other elite trainers vary and they are found on the table within the instructions for the sensor)
So on the pairing screen the sensors that were found without having to do anything other than a search were the HRM and the GSC10 and a Elite Real Power sensor.
The Elite Power Sensor is not the one to select
Go into the Power Meter Sensor search and turn your cranks miraculously a new sensor appears in the list as a generic power meter and you will also see a power measurement in response on this sensor and not and not on the Elite sensor that is listed there.
Select the generic sensor and you should be good to go.
I don’t know why the generic sensor does not appear automatically and needs the cranks turning that’s something for Zwift to sort out. Previously it never appeared regardless of the cranks turning