Thanks to everyone for all your comments on this.
Based on what I have, I think EK would find it hard to utter the 'exceptional circumstances' word.
Someone failed on their risk based alternate selection process. 1. Safety, 2. regulatory compliance and 3. commercial requirements.
DXB-RKT = 70km alternate for EK162 ex DUB result = DUB-DXB journey time of 21.5 hours.
DXB-AAN = 112km (alternate for EK2 ex LHR = fuel and go.
DXB-AUH = 116km (alternate chosen by EK748 ex Tunis = fuel and go.
Sharjah must figure somewhere as an EK alternate but does anyone know if there are others?