Although I saw a prototype in October 1975 at RAFC Cranwell when HSA were trying to flog it to the Swedish Air Force (we'd taken a Gnat and Hunter T7 over from Valley for comparison), the first time I saw an RAF Hawk was in late 1976 when one did a PD at RAF Honington. I'm not sure when HS.1182 became 'Hawk', but I heard later that someone in the mad MoD box wanted it to be named 'Tercel'...
The ones I flew were at Valley and Chivenor 1980 - 1981, so had the dreadful pre-AHARS compass system and the smaller fin trailing edge fillet. But were very agile and had superb range. A brilliant little jet, but why-oh-why no offset-TACAN, the Gnat student's friend!