Bellip was a Phoenix colonist who met the Fifth Doctor, Erimem and Peri on Medusa space station. Like all colonists there, she lived in a state of profound isolation, almost never leaving her room. She was romantically attracted to Laroq, but didn't possess the social confidence to leave her room and interact with him in person until the arrival of the time travellers.
She met Peri first, who spent a good deal of time trying to understand her unusual social isolation. Peri tried her best to be understanding of her new friend's social estrangement, but there were clearly times where the American's frustration shone through.
Of the three colonists encountered by the TARDIS crew, she had the most extreme case of agoraphobia, and seemed to lack even the basic curiosity of either Laroq or Vidler.
Though she told Peri that she could not remember having parents, Auntie told the Doctor that Bellip was her biological granddaughter — the daughter of her daughter. Bellip, like all the rest of the colonists, was actually from Earth, and had arrived at Phoenix in a state of cryogenic sleep. Memory of her origins was lost both through her long sleep and the mental conditioning that social isolation engendered. (AUDIO: Three's a Crowd)