Delia also co-wrote some of the songs on the White Noise album, as discussed in this article from Sound on Sound:
"There is a big difference between musicians who happen to use synthesizers and musicians who make electronic music. Although David Vorhaus started out as a classical bass player working with symphony orchestras, a chance encounter plus his background as a physics graduate and electronic engineer steered him inexorably in the direction of electronic music. "I guess it started around 30 years ago when I met Brian Hodgson and Delia Derbyshire, who were then in a band called Unit Delta Plus," he recalls. "I was on my way to an orchestral gig when the conductor told me that there was a lecture next door on the subject of electronic music. The lecture was fantastic and we got on like a house on fire, starting the Kaliedophon studio about a week later!"
Brian and Delia worked with David on his early recordings at the same time as they were working at the BBC's Radiophonic Workshop. David's introduction to commercial recording came about because Island Records' Chris Blackwell was so enthused by their approach to electronic music that he offered them an album deal with what was then a significant advance. In 1969, David released White Noise: An Electric Storm. This was followed by White Noise 2 in 1975 and White Noise 3 in 1980, and David has just released White Noise 5: Sound Mind. As well as being available in record shops, a library version is also available through Music House under the name Science Friction. Between albums, David has written a lot of music for TV and film: his music features on a number of high-profile TV commercials as well as on TV themes. David also plays live under the White Noise mantle."
According to one of my friends who's been into electronic music since god knows when, White Noise was originally Delia's project that Vorhaus was brought into for his engineering skills, then proceeded to take all the credit and waltzed the band name out from under her. No idea if there's anything to back up that theory.