Sorry late reply to this thread but not been home much recently,as referred to in my earlier post about production tolerances - I seemed to remember that during the Hawk flight testing there had been a fairly large difference with stalling characteristics between particular Hawks but I did not want to say too much without having a reference to use...
From Arthur Reed's book 'BAe Hawk' (Ian Allan,Modern Combat Aircraft 20)
Phase 4 of Hawk development began with the first flight of XX157 in april 1975.Although XX154 had achieved a satisfactory standard in handling at the stall,it soon became apparent that subsequent a/c were not consistent in their behaviour ,particularly in the approach configuration with u/c and full flap.
On one occasion this a/c pitched nose down over the vertical with full back stick,before recovering when flaps were retracted.
The problem was effectively cured by removing the outboard section of the flap vane.
As a further precaution the tailplane travel was reduced from minus 17 deg to minus 15 deg.
Arthur Reed was a highly respected aviation correspondent/journalist btw