An employee who is dismissed shall be regarded for the purposes of this Part as unfairly dismissed if the reason (or, if more than one, the principal reason) for the dismissal is that the employee—
made (or proposed to make) an application under section 80F,
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
brought proceedings against the employer under section 80H, or
alleged the existence of any circumstance which would constitute a ground for bringing such proceedings.