HB, although I understand your suggestion, it would be a far from simple matter to modify the control column as you suggest. There would also be considerable risk of sunlight reflections causing distraction. When glued to a mate's wing, the last thing you would want would be a sudden flash in your peripheral vision from the lower cockpit area.
I only did 145 hrs on the Hawk 30+ years ago during a Valley refresher and at Chivenor, but I don't recall a single instance of a problem checking that the seat firing handle was correctly stowed and pinned.
I don't believe that there is a significant problem, provided that there is sufficient 'timeline' allowance for the pre-flight checks to be carried out diligently.