I read the diagram in the report/bulletin as the tick marks showing the "every six seconds" radar returns. Six seconds of flying can include some corrections, so the altitude at entry may not be 200', but another value. Won't guess as to what AH saw on the altimeter at the point of 'initiate the maneuver."
It commenced a gentle climbing right turn to 1,600 ft amsl, executing a Derry turn to the left and then commenced a descending left turn to 200 ft amsl, approaching the display line at an angle of about 45º. The aircraft then pitched up into a manoeuvre with both a vertical component and roll to the left, becoming almost fully inverted at the apex of the manoeuvre at a height of approximately 2,600 ft amsl.
The radar track isn't the same as a continuous ground track display.