The C-130 took off at 05:10 and crashed 1:45 hours later. Which means at around 06:55. The chances of anyone at Chivenor being rounded up to generate a Hunter at that time on a Friday morning, in time to be armed, take-off and make a visual intercept are zero.
Ball ammunition was invariably used for range firing, rather than HE. F6 only flew with one gun available, although the FGA9 might have had two available. So spotters, sorry but no way would a Chivenor Hunter with 4 x 30mm Aden cannon with HE rounds have been available at that time of day!
The Hunter myth is clearly total bolleaux!