Oladini
Miss Oladini was a human former mathematics student turned assistant originally from Nigeria. In the 2000s, she came to the United Kingdom to go to university, but lost her status and remained in hiding in the country illegally. Working for the Lovelace Agency in Brentwood to learn new skills, Miss Oladini got a job on a short-tern contract working for Professor Brian "Ahab" Melville at the Copernicus Array, despite being uninterested in astronomy.
Miss Oladini made sure Professor Melville had tea and chocolate bars and listened to him talk about his cat and his mother, unaware that the Professor was exaggerating his supposed dottiness. Due to her job, she found herself involved in helping the Tenth Doctor stop an attempt by the re-emergent Mandragora Helix to conquer the Earth, after which he arranged for UNIT to fix her status so she could stay in the UK. (PROSE: Beautiful Chaos)