Holly Aird (Dr. Wharton) was expecting her second child during season four which is why in season four her character is nearly always seen standing behind something (or someone in walking shots) or wearing large coats and lab coats.
Dr. Frankie Wharton:
All right, Spence?
Dr. Frankie Wharton: Who?
DS Spencer Jordan: Mel
In episode Magdalene 26 S8 the both women claim they were 15 on January 14 1967 when both men died. However according to their birth register which can be seen by the nun who is writing this down in a book, the date of birth is may 1952, thus making the women 14 instead of 15 at the time.
US broadcasts were cut down to approximately 50 minutes per episode to allow room for commercials.