Twinact,
I concur with your view.
If Ark Royal is correct then, given the Wx forecast provided for the flight (in particular the possibility of localised low cloud around the Mull); one has to question whether the decision to conduct the flight in that way was a sound decision.
Given the forecast, there was a distinct possibility of a low level Wx abort and an enforced climb to Safety Altitude. If the icing clearance precluded this then the decision to fly that route was clearly flawed.
It is ironic that the failure to conduct the required "outbrief" precluded the possibility of this being reviewed. Moreover, it also precluded any review of the crew duty considerations and its potential effect on aircraft availability should the aircraft be forced to nightstop outside the Province.