More a FYI for any other Fiesta owner, when you install the dongle you can't close the coin flap, it fouls on the latch mechanism, you'll need a low profile OBD extension of you want to keep the coin tray.
You may be able to modify the cut out /latch / opening handle section, but that's a bit permanent and may be an issue if you sell the car. You could also remove it but its a useful coin holder pocket...
Thanks very much for this feedback. Did you end up using an OBD extender?
Please note that if you use an extender, you will need to secure the GOFAR dongle to the car so that it is rigid, otherwise GOFAR's accelerometer will not function correctly.