Not according to the gov.uk website nennypops. It says "You should try and [ sic ] sort any issues out by speaking to your employer to solve the dispute." but then goes on to say :
"If you do have a case for constructive dismissal, you should leave your job immediately - your employer may argue that, by staying, you accepted the conduct or treatment."
So, on the contrary, Kathy might have stuffed her chances by being too accommodating. Also if she skips straight over to GG then there will not be much in the way of 'loss of earnings' so I'm not sure that she would be entitled to much compensation (although if she had the guts, which is a big 'if', then she could threaten legal action and BL would pay her a chunk of money to make her go away).