Question: Who wrote the home demo of the song that was first released after the Beatles informally decided to split?

Context articles: Hello Little Girl
Nephew discography
In the Beginning (Circa 1960)
A Sorcery Written in Blood
Free as a Bird
The Disappointed (song)
Morning Symphony Ideas
Break-up of the Beatles
My Favourite Waste of Time
Strid (band)

"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.
The Danish rock band Nephew has released five studio albums, three live albums, five EPs, one compilation album, one box set, and nineteen singles.
 The band was formed in 1996 by Simon Kvamm, Kristian Riis, Jonas Juul Jeppesen, and Søren Arnholt.
 In 1998, Jeppesen, who was until then the bassist in the band, left the band and was replaced by the current bassist Kasper Toustrup.
 That year, they proceeded to release two demo albums, "Tunes" and "Things to Do"; the demo "Downtown Europe" was released in 1999.
 In 2000, the band debuted with "Swimming Time", on the small label Martian Records.
 The album was received well by both critics and fans, but despite the band's success, the members got bored and decided to take a break.
 During their 2001 farewell concert in Germany, the band rediscovered their passion for music and decided to stay together.
 After being signed to Copenhagen Records, the band released their second studio album "USADSB" in 2004, which was very well received and is seen as their "breakthrough" album.
 It gained double platinum status in Denmark, and aside from there has been released in Japan, Germany, and Norway.
 Later in 2004, the "En Wannabe Darth Wader" single release came to be, which contains both the Danish and English versions of Nephew's song "En Wannabe Darth Vader".
In the Beginning (Circa 1960) is the first consolidated American packaging of the 1962 German album by Tony Sheridan and The Beatles (credited as The Beat Brothers), called "My Bonnie".
 "In the Beginning (Circa 1960)" was released by Polydor Records in 1970 (catalogue number 24-4504.)
 It was recorded in Hamburg in 1961.
 This album was originally released as "The Beatles' First" in Germany in 1964 and in the United Kingdom in 1967.
 Previous American releases of this material in LP form was split in 1964 between MGM Records and Atco Records.
 Polydor (which eventually absorbed MGM) established its United States branch in 1969 which explains why this package was released much later in The Beatles' history.
 Most of the tracks feature vocals by Sheridan.
 The album was released only four days before "Let It Be", The Beatles' final studio album.
 This is therefore the last Beatles compilation album released whilst the band were still releasing studio albums.
 All subsequent releases of Sheridan/Beatles/Beat Brothers material are simply repackages of the same tracks.
 This album is available in a slightly altered CD by Polydor without the inaccurate "(Circa 1960)" subtitle and with both parts of "Ya Ya".
 Only part one of that track was released on this LP.
 "In the Beginning (Circa 1960)" was also the only Beatles album not owned by EMI though Universal's purchase of Polydor and the Beatles' main catalogue put them under the same ownership.
A Sorcery Written in Blood was the first demo released by Norwegian black metal band Gorgoroth.
 The title of the demo was taken from the lyrics of the song "The Return of Darkness and Evil" by the band Bathory.
 The demo was released in 1993 as a limited edition hand-numbered cassette.
 A 7" vinyl bootleg also existed; however, there were no official reissues.
 Due to the Satanic imagery used on the demo cover, the newspaper "Firda" in Førde in Sogn og Fjordane, Norway, ran a front-page story on the demo and Gorgoroth on 7 January 1994.
 The demo led to the band landing a record deal with French record label Embassy Productions.
 The track "Sexual Bloodgargling" was an early version of the song "Ritual", re-recorded for Gorgoroth's first album "Pentagram".
"Free as a Bird" is a song originally composed and recorded in 1977 as a home demo by John Lennon.
 In 1995, a studio version of the recording, incorporating contributions from Paul McCartney, George Harrison and Ringo Starr, was released as a single by the Beatles.
 It was released 25 years after the break-up of the band and 15 years after the death of Lennon.
"The Disappointed" is a song by XTC from their 1992 album "Nonsuch", with the home demo later released on "Coat of Many Cupboards" (2002).
 It reached No. 33 on the UK Singles Chart, reached No. 1 on the Rolling Stone College album chart, 32 on the ARIA Charts, 68 on the Dutch Top 40, and reached No. 97 on the Billboard album chart in the United States.
 It was also nominated for an Ivor Novello Award in 1993.
 It also appears on the compilations "" (1996) and "Upsy Daisy Assortment" (1997).
Morning Symphony Ideas is a posthumous compilation album by Jimi Hendrix, released on July 25, 2000 by Dagger Records.
 The album contains previously unreleased studio and home demo recordings.
 "Keep on Grooving" was later featured on the companion CD to the 2007 book "Jimi Hendrix: An Illustrated Experience".
The break-up of the Beatles was a cumulative process throughout the period 1968 to 1970, marked by rumours of a split and ambiguous comments by the Beatles themselves regarding the future of the group.
 Although in September 1969 John Lennon privately informed the other Beatles that he was leaving the group, there was no public acknowledgement of the break-up until Paul McCartney announced on 10 April 1970 he was leaving the Beatles.
"My Favourite Waste of Time" (also known as "You're My Favourite Waste of Time") is a song written and first released by American singer Marshall Crenshaw.
 His 1979 home demo of the song was released as the B-side of his 1982 hit "Someday Someway".
Strid is a Norwegian black metal band that was originally known as "Malfeitor" from 1991 to 1992.
 After releasing two demos - "Malfeitor" (in 1991) and "Pandemonium" (in 1992), they changed their name to "Battle" and there were some line up changes at the time.
 In the year of 1992 the band released the "End of Life" demo.
 The demo contains only one song which is around 11 minutes.
 The line up at the time of recording the demo was: Storm - on bass and vocals, Lars Fredrik Bergstrøm - on guitars and Jardar - on drums.
 The guitars were written by Lars Fredrik Bergstrøm (1974 - 2014).
 In 1993 the band changed the name to "Strid" which means "Battle" in Norwegian.
 That same year, Strid re-released their "End of Life" demo under their new name, through the German label "Malicious Records".
 After releasing the "End of life" demo, Lars Fredrik Bergstrøm left the band and was replaced by Ravn Harjar.
 Through the years between 1993 and 1995, the band writes and records the self-titled EP which was released through Malicious Records and contains only two songs - "Det hviskes blant sorte vinder" which means "It Is Whispered Amid the Black Winds" in Norwegian and "Nattevandring" which means "Nightwandering" in Norwegian.
 The music style and sound of this demo is more ambient/atmospheric black metal oriented.
 Mainly because of this release, the band is commonly recognised as the creators of depressive black metal along with some other bands from the second wave of black metal music.
 At this time the band line up contains: Ravn Harjar - on guitars, Storm - on bass and vocals and Jardar - on drums.
 After the releasing of the self-titled EP, there was no any official releases by the band.
 There are also bootleg releases that came out through the years like the CD from 2005 by Ars Mysteriorum and LP, each featuring both "End of Life" and the self - titled EP tracks.
 In the year of 2001 the original former member of "Malfeitor/Battle/Strid", bass player and vocalist - Storm committed suicide.
 In the year of 2007, the Greek label Kyrck Productions & Armour re-released all the previous material released by the band from the past which contains all "Malfeitor/Battle/Strid" material.
 Somewhere between 2009 and 2010 there was a reunion of the band with old members including Vicotnik (Dødheimsgard, ex-Aphrodisiac, ex-Ved Buens Ende, ex-Manes, ex-Code, ex-Naer Mataron, ex-Endwarfment).
 Another member that was part of the reunion was Lars Fredrik Bergstrøm - the main composer of the "End of Life" track.
 In 2014 Lars Fredrik Bergstrøm died.
 At this time the band line up contains Ravn Harjar - on guitars and vocals, Vicotnik - on bass and Sigmund (ex-Inflabitan, ex-Dødheimsgard) - on guitars.
 In January 2015, Ravn Harjar wrote a statement on the official Strid Facebook page that in the autumn of the year 2015 the band will start recording their first full-length album which will be titled "Endetid".
 That means "End of times" in Norwegian.