Were you wrong to go back? I can't say you were but I don't know the status of the Airport you went back to.
Would you be wrong to go on? I can't say you would be as if you lost the remaining Eng Gen then you'd still have the Emerg Gen at 8.6 kva or if the Green Hyd also failed 3.5 kva ( via the RAT ) to get to the nearest Airport.
I can see how a commercial operator would prefer you continue but at the end of the day if you can JUSTIFY YOUR DECISION then do whatever you are comfortable with.
Sometimes these things are deliberately left in a grey area to give the Commander some wiggle room in his decision making. i.e its up to you to exercise good command judgement and decision making on the day.