“(3) Notwithstanding subsection (2A), where an employee establishes to the satisfaction of the Tribunal—

(a) that failure to make a claim for a lump sum before the end of the period of 104 weeks mentioned in that subsection was caused by his ignorance of the identity of his employer or employers or by his ignorance of a change of employer involving his dismissal and engagement under a contract with another employer, and

(b) that such ignorance arose out of or was contributed to by a breach of a statutory duty to give the employee either notice of his proposed dismissal or a redundancy certificate,

the period of 104 weeks shall commence from such date as the Tribunal at its discretion considers reasonable having regard to all the circumstances.”.