rudderrudderrat,
Yes. That the PF was struggling with roll-control may have overloaded him. Later, at very high AoA, resultant sideslip would add to probe problems, as has been said. At that stage, was the use of aileron/spoiler productive, counter-productive, or irrelevant?
I'm interested in your rudder-trim argument, but don't see how it would counter wing-drop if the latter was caused by turbulence.
BOAC,
The 210kt crossover seems to be a popular figure. I think there must be a gradual blending-out/blending-in process, to make it seamless to the pilot (which it is). But, as I said, what logic is applied when/while airspeeds have been declared invalid?