Does dismissal for absences due to post-natal depression arising after maternity leave amount to sex and/or pregnancy and maternity discrimination?

Under Article 5A of the Sex Discrimination (Northern Ireland) Order 1976, pregnancy discrimination occurs where an employer treats an employee unfavourably because of her pregnancy or because of an illness she has suffered as a result of her pregnancy during the “protected period” i.e. from the beginning of pregnancy to the end of her maternity leave (including any additional maternity leave).

Illness after the end of the maternity leave will not be protected. In the case of a woman, direct sex discrimination occurs where, an employer treats her less favourably than it treats or would treat others as per Article 3(1)(a) Sex Discrimination (Northern Ireland) Order 1976.

This female employee