Also don't blame the THS trimming up to 13 deg nose up. It was a result of the Pilots demanding back stick pitch up ( to counter what they thought was an overspeed ) the speed obviously decayed during the manoeuvre requiring more and more trim to help it satisfy the Pilots demand.
Sounds good in theory/normal operations but goes against the normal rules of flight, being if you pull back the system resists until you make the conscious effort to trim into the pull. If you let go without trimming, the nose goes back to where it was (or at least tries to).
In this case, the system trimmed full nose up and stayed there. That doesn't sound like a good idea to me and wouldn't have helped any nose down recovery effort by the crew, at least in the initial bit at the top of the zoom. They wouldn't have had to hold in a shedload of forward stick to get the thing to start trimming nose down.