Well, the original idea had been to replace the Gnat in the advanced training role....with the Jaguar! I can just remember seeing a poster in about 1968 which showed a Jaguar in grey and dayglo......
Fortunately They realised that it would be far too complex, so along came an Air Staff Requirement which led to the HS1182.
The original name was to have been 'Tercel' - a male falcon. Fortunately They said No - so HS1182 became the Hawk T Mk 1.