Hi Oggers, I seem to recall that during an AAIB report into a fatal accident at our local airport, it was mentioned that any bank exceeding 5 degrees into the bad engine would be irrecoverable, and the airplane would continue to bank until inverted, which is what actually happened here. I will see if I can unearth the AAIB Report, to provide a reference.
.edit...
Well I've looked and looked but can't find the proof I am looking for, but did find this interesting presentation on Vmca, and how it is at a minimum at 5 degrees
into the good engine.....
https://www.youtube.com/watch?time_continue=2&v=Wbu6X0hSnBY
.