Question: What is bass player Stuart Sutcliffe often referred to, thanks to his presence on a band's early demo recordings?

Context paragraphs:
Flamingo Drive: Flamingo Drive were a London Indie/Psychedelic band.  They featured Bobby Grindrod, ex of Friends of The Bride and The Fog Band, who maintains his unique and exquisite vocal style.  Matt Wood, of the Black Country experimental/garage rock band The Nightingales is the group's guitarist.  On the basis of some early demo recordings, respected London indie collective Sounds XP wrote a glowing review, pointing to a bright future for the band.  From these initial indie-pop beginnings, recent shows have seen psychedelic and library music elements become more important in the sound.

Volume 2 (CKY album): Volume 2 is a compilation album by American heavy metal band CKY.  It was released by Distant Recordings and Teil Martin International on February 27, 1999, the same day as the band's debut studio album "Volume 1".  The album features a number of early demo recordings, as well as skits and samples from the first "CKY" video, and recordings of prank calls performed by Brandon DiCamillo.

Sky and Trees Records: Sky and Trees Records is a record label set up by United Kingdom band Chumbawamba in 1983.  The band used the label to release and distribute a number of cassettes and booklets by themselves (see also Cassette Culture), including their early demo recordings "Be Happy Despite It All" (1983), "Another Year Of The same Old Shit" (1984) and the 'cassette single' "Common Ground" (1984), which was a benefit for striking miners (see UK miners' strike (1984-1985)).  They also released material by other anarcho-punk performers, including their 'sister' band The Passion Killers, Antidote and an animal rights benefit compilation, "The Animals Packet".  The only vinyl release on Sky and Trees was Chumbawamba singer Danbert Nobacon's solo album "The Unfairy Tale" (1985).

Hokej klub Virginitas: Hokej Klub Virginitas ("Hockey Club Virginity") is a semi-official compilation album by the Serbian new wave/post-punk bands La Strada and Luna, released in 1988 by Ding Dong Records.  The compilation, available on compact cassette only, features recordings made by La Strada at the Peđa Vranešević studio in Novi Sad, consisting of the tracks "On" ("Himself") and "Sat" ("Clock"), Luna recordings "Spori Metropolis", recorded at the Ben Akiba theatre June 27, 1983, an entire March 11 performance at the KCM Sonja Marinković, and the band's early demo recordings made at the Radio Novi Sad and Meta Sound Studio during 1982 and 1983.

Anthology 1: Anthology 1 is a compilation album by the Beatles, released on 20 November 1995 by Apple Records as part of "The Beatles Anthology" series.  It features rarities, outtakes and live performances from the period 1958–1964, including songs with original bass player Stuart Sutcliffe and drummer Pete Best.  It is the first in a trilogy of albums with "Anthology 2" and "Anthology 3", all of which tie in with the televised special "The Beatles Anthology".  It contains "Free as a Bird", billed as the first new Beatles song in 25 years.  The album topped the "Billboard" 200 album chart and was certified 8x Platinum by the RIAA.

Hello Little Girl: "Hello Little Girl" is the first song written by John Lennon, and credited to the Lennon–McCartney songwriting partnership.  According to Lennon, he drew on an old "Thirties or Forties song" that his mother sang to him.  Written in 1957, it was used as one of the songs at the Beatles unsuccessful Decca audition in 1962.  They recorded a home demo of it, with Stuart Sutcliffe on bass, which is available only on bootleg currently.

Stuart Sutcliffe: Stuart Fergusson Victor Sutcliffe (23 June 1940 – 10 April 1962) was a British painter and musician best known as the original bass guitarist for the Beatles.  Sutcliffe left the band to pursue his career as a painter, having previously attended the Liverpool College of Art.  Sutcliffe and John Lennon are credited with inventing the name, "Beetles", as they both liked Buddy Holly's band, the Crickets.  The band used this name for a while until Lennon decided to change the name to "the Beatles", from the word "beat".  As a member of the group when it was a five-piece band, Sutcliffe is one of several people sometimes referred to as the "Fifth Beatle."

Horrors of Hell: Horrors of Hell is a compilation album by the American death metal band Vital Remains, consisting of early demo recordings.  It was released in 2006 by Century Media.  All tracks are remastered, and the album is limited to 5000 copies.

The Plan (Tubeway Army album): The Plan is a retrospective album of early demo recordings by Tubeway Army (the band name originally used by Gary Numan) released in 1984.

Collectybles: Collectybles is a compilation album by the American Southern rock band Lynyrd Skynyrd, released on November 21, 2000.  The two disc set includes early demo recordings, live versions and studio tracks, some previously unreleased.

Supporting paragraphs: Hello Little Girl Stuart Sutcliffe
Answer: Fifth Beatle