For the purposes of the 6-month time limit in section 135(5), the date on which the cause of action for the recovery of the penalty first became known to the employee, or should reasonably have become known to the employee, must be taken to be a date after, as the case requires,—
(a)
the relevant date under section 69ABG(3); or
(b)
the applicable date under section 69ABI(3)(a) or (b).