Did they only use Amy in the UK comics because the people who did fleetway comics couldn't get the rights from DIC or Archie comics to use Princess Sally as the recurring female character and love interest to Sonic
No. Unlike SatAM or Archie, Fleetway loosely followed the storyline of the games. You're thinking of Snively, who was originally supposed to be in the Fleetway Comics. They couldn't get the rights, so Grimer was created to be Robotnik's assistant instead. Before Amy's debut in Sonic CD, she was his girlfriend in the Shogakukan manga.
