"Here We Go" was due to be released as a single in June 2000, but the release fell through. The song later became the basis for the theme tune to the hit cartoon series "Totally Spies!" in 2001. The deal with London Records and Xenomania ultimately fell through. Following the demise of their deal with London Records, Cooper and Higgins began writing and producing for other artists. Cooper has been described as the "chief lyricist" of Xenomania, who are based out of a converted mansion in Kent. Cooper co-wrote the song "Round Round" which became a number one hit for the Sugababes in 2002. Xenomania continued their commercial breakthrough by writing "Sound of the Underground" for "" winners Girls Aloud; the song spent four consecutive weeks at number one. Since 2002, Xenomania have been recurring collaborators of Girls Aloud. Miranda Cooper co-wrote all of Girls Aloud's original singles up until their hiatus in 2009, including the BRIT Award-winning number one "The Promise". Cooper also co-wrote another number one single for the Sugbabes, 2003's "Hole in the Head", as well as the singles "In the Middle" and "Red Dress". In 2011, Cooper worked with girl group The Saturdays, co-penning the single "All Fired Up", and boy band The Wanted. Cooper has also co-written songs for prestigious artists such as Kylie Minogue and Pet Shop Boys, including the singles "Giving You Up" and "Love Etc." Xenomania have also helped launch the careers of "The X Factor" contestant Amelia Lily and Australian singer-songwriter Gabriella Cilmi. Cooper's songs have spent more years on the English chart than any other female songwriter in history. In 2007, "Harper's Bazaar" wrote: "If it's a hit you want, you'd better talk to Cooper. For the rest of us, Cooper has the power to get a tune inside our heads." In May 2018, a stage musical adaptation of the film "Son of Rambow" was workshopped at The Other Palace in London which featured music and lyrics by Cooper (with previous writing partner Nick Coler and writer Richard Marsh). Cooper and Coler also wrote the music and lyrics for the musical adaptation of David Walliams' book "Billionaire Boy" which will premiere at the Nuffield Theatre, Southampton (City theatre) for Christmas 2018.