Was in a relationship with actor Stewart Bevan who played Professor Cliff Jones on her final Doctor Who serial The Green Death. They remained good friends until Bevan's death in 2022.

In common with her Doctor Who (1963) co-star Nicholas Courtney, she trained at Webber Douglas Drama School.

Aged 16, she was involved in a serious car accident after the driver fell asleep at the wheel. Manning was thrown through the windscreen of the car and ended up on the bonnet, breaking her back and both her legs as well as severe facial disfigurements. She had to undergo plastic surgery and spent nearly two years recovering in hospital.

Childhood friend of Liza Minnelli.

Dated Jimi Hendrix in the 1960s.

Partner of Barry Crocker since 1989.

Became close friends with Jon Pertwee while filming Doctor Who (1963).

Sprained her ankle during her first scene filming Terror of the Autons: Episode Three (1971).

Named Terror of the Autons: Episode One (1971), The Mind of Evil: Episode One (1971) and The Green Death: Episode One (1973) as her favourite episodes of Doctor Who (1963) in which she appeared.

Originally given a small role as a French au-pair girl in one episode of Man at the Top (1970), however she impressed the producers during rehearsals so they instead gave her a different substantially larger role in two episodes.

Manning suffers from nearsighted vision.

Reprised the role of Jo Grant in The Sarah Jane Adventures (2007).

Straight after leaving Doctor Who, she presented her own television show on crafts called Serendipity (1973).

Whilst commentating on The Three Doctors she claimed William Hartnell died "about three weeks" after the show. Even though survived until 1975.

Offered a role in Home and Away (1988) while living in Australia but had to turn it down due to theatre commitments.

Appeared in several television commercials for ITV in the late 1960s including one for the Egg Marketing Board with Jacqueline Bisset.

Auditioned for the role of Rosie Dixon in Rosie Dixon - Night Nurse (1978).