DI Menzies met the Sixth Doctor when she arrested him for murder on 29 February 2008. Gradually, she came to understand that he was not a criminal, but a time traveller who could help her uncover the truth of the murder, which involved several aliens who had invaded Manchester. (AUDIO: The Condemned)
She encountered the Doctor and Charley Pollard once again a short time later, when a pound coin from 2012 appeared in a coin-operated vending machine four years too early. That anachronistic coin led the Doctor, Charley, and her into the middle of a war between the Cyrox and the Tabbalac, with Earth as its battleground. After the war was ended, Menzies asked the Doctor if she could travel with him. The Doctor politely refused, citing the growing mystery surrounding Charley's true identity, but indicated that one day he might take her up on the offer. (AUDIO: The Raincloud Man)
Menzies was called from Manchester to London after John Fielding asked to speak to a member of the police who knew of the Doctor. She became aware of the time breaks and encountered the Doctor and Charley again. After travelling through the breaks, she returned to 2009 with Wadmore, with Charley believing that romance would blossom between the two. (AUDIO: The Avenues of Possibility)
Menzies was possessed of an earthy, sarcastic personality, fueled by her love of a good pint. She was a generally by-the-book detective, but could, when necessary, break the rules if she thought it would help her get to the truth of a case. Specifically, she allowed the Doctor, although a murder suspect, access to the evidence against him on the hunch that he might have been able to help her find some answers. This severe breach of protocol was met with a stern reaction from her boss, DCI Turnbull. (AUDIO: The Condemned)
This isn't to say that she followed the Doctor's lead blindly. Indeed, she found it necessary to rein the Doctor in when he was proceeding with his investigations in a way that wouldn't produce evidence that could stand up in court.
Her reaction to the true nature of the the Doctor's "police box" and to his own alien-ness was matter-of-fact. She quickly grasped some of the fundamentals of time travel, based in part on having seen the science fiction film Back to the Future, and treated alien threats as any other criminal problem that she might have to deal with in the normal course of her duties. (AUDIO: The Raincloud Man)