Dairyground,
the list that you quoted from another poster is not the same sequence as would have been taught to the crew of IO.
SOPs evolve in the light of experience but cannot cater for every eventuality. Statistically speaking it’s best to stop the aircraft apply the park brake make a PA ( I know I know but it’s the BA way) then diagnose the malfunction and call for the memory drill or ECL. The reason is that this “cages the chimp” and manages workload effectively.
IOs problem was the fuel leak unfortunately there isn’t an easy way to diagnose this event from the flight deck except by external observer or as in this case the ensuing fire caused by the leaked fuel. HTH