Surely the 'pause' in the climb is as a result of selecting an accelerative attitude at TDP.
Also, if you think you have a control problem at night at a critical stage of flight, I would suggest the natural reaction would be to get away from the ground while you sort it out.
From the preliminary AAIB report:
"The helicopter then began a climb on a rearward flight path2 while maintaining a northerly heading. Gear retraction started as it passed through a height of approximately 320 ft. The climb then paused. Heading changes consistent with the direction of pedal movements were recorded initially, then the helicopter entered an increasing right yaw contrary to the pilot’s left pedal command. The helicopter reached a radio height3 of approximately 430 ft before descending with a high rotation rate."
There seems to have been an increase of 110 feet RADALT after the TR event. However, as someone pointed out, the surface beneath the helicopter is not even so it could also be a Red Herring.