A few things come to mind. If there was no earth to the spur the Europa would show a warning message on power up as it would detect the missing earth. The fact that the first part of the in-situ test did not flag up a warning also makes me think that there is an earth to the spur. If the oven passed an in-situ eath test on your Europa, this tends to suggest the Europa is functioning correctly.
I'm can't think of any reasons why the metal parts of a fridge would not be earthed - this would only allowable if the exposed metal parts of the fridge were double insulated from mains.
The sensible approach would be as you suggest - to have the fixed wiring checked out in case there is a wiring fault.