Tina Drake

 was a Time Agent who was sent to find investigate a temporal anomaly. She was angry when the Fifth Doctor told her that her fake name translated to Grapefruit and not was a place in the Dordogne. She escaped before being frozen with the Doctor. She couldn't follow the Doctor to the future, so went back to the 51st century to do some more investigation before rejoining him in the 18th century. She accompanied both the Fifth and Tenth Doctor to find out when the Cybermen first contacted him. (AUDIO: The Gates of Hell)