oscarh
I assume that you have read the report, but the bit that concerns me was the comment
Once all the passengers had disembarked both flight crew attempted to disarm the door and both confirmed they were unable to successfully do so
Therefore
both flight deck members knew that the door was faulty - this is not a 'grey area' - if the door is u/s then it
must be considered an inoperative exit in accordance with the MEL.
The Captain did not have the training to assess whether the door was serviceable, so in the absence of a engineer then the door should have been assumed to be u/s and properly deferred in the aircraft log.