After his death his younger brother, Gerald, was left with the daunting task of finding a new home for the collection.
He found approximately 27,000 7ins vinyl singles and 8,000 12ins singles neatly filed in alphabetical order on purpose built floor-to-ceiling shelves that covered the four walls of Keith's lounge.
More than 10,000 CD singles from the 1980s to present day also filled up a spare bedroom of his modest home in Twickenham, south west London.
There were dozens if not hundreds of CDs still in their cellophane wrappers from where he hadn't had the time to open and listen to them.
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Keith had safely stored the covers for most of the singles and replaced them with white sleeves on which he wrote the date the song was released and the chart position it achieved.
Auctioneers now selling the collection don't believe there is a single single missing, although it would take weeks to trawl through it all to make absolutely sure.
There are approximately 27,000 7ins vinyl singles and 8,000 12ins singles in the lounge alone (BNPS)
The archive contains the good, the bad and the downright ugly that graced the shelves of record shops across Britain for over six decades.
There is everything from Abba to ZZ Top, including all 39 Beatles singles and re-released singles, the 52 Rolling Stones' chart hits and the 72 songs released in the UK by Elvis.
Iconic number ones include Abba's Waterloo, Bohemian Rhapsody by Queen, Relax by Frankie Goes to Hollywood, Bony M's Rivers of Babylon and Michael Jackson's Thriller.
There are also the record-breaking singles that remained at number one the longest; I Believe by Frankie Lane in 1953, Bryan Adams' I Do It For You in 1991 and Love Is All Around by Wet, Wet, Wet in 1994.
The collection contained the good, the bad and the downright terrible of the music industry (BNPS)
And there are also more dubious tracks of our time such as the Wurzels' Combine Harvester, the Birdie Song, Agadoo, Bombalurina, Clive Dunn and a Tribe of Toff's John Ketley is a Weatherman.
Alastair McCrea, of Ewbanks Auctioneers of Woking, Surrey, was invited to Mr Sivyer's three bed house to value the collection.
He said: "The front room was wall to wall covered with shelves with the seven inch singles on, the only space that wasn't taken up was where the window was.
"It really was impressive to look at.
"These days most people have their entire record collections stored on a small digital device in the living room that can been accessed remotely.
"Apparently, Mr Sivyer was not that up on technology and terms like 'downloads' and 'back-up' would have been completely foreign to him.
Keith Sivyer's collection eventually graduated from the lounge and took over the second floor of his house
"It was a passion and an obsession for him.
"We believe the collection to be one of the most complete and possibly unique in private hands in the country. We can't guarantee for sure it is absolutely complete because it would take months to go through every one but we think it is."
Keith started his collection in 1954 and retrospectively bought all the singles that had entered the charts for the previous two years.
He used to walk into Earfriend record shop in Twickenham every Thursday with the latest copy of Music Week and buy all the new release singles in the charts for that week.
Record shop owner John Carroll got so used to Keith's custom he put the records aside for when he came in.
As his collection grew Keith naturally became a mobile DJ although he worked for 37 years as an airside worker for British Airways at Heathrow.
When he divorced from his wife in the mid 1970s he moved back in with his mother Louise along with his collection.
Keith naturally became a mobile DJ although he worked an airside worker for British Airways at Heathrow (BNPS)
His brother Gerald, a 68-year-old retired builder, said: "It became an obsession with him. He must have spent an absolute fortune by the end.
"Most of the singles were bought in the week they were released from a record shop called Earfriend.
"When the shop closed, he started buying them from Woolworths and then off the internet in recent years.
"I had to reinforce the floor of the house at one point because of the weight of the boxes he kept some of the the records in.
"He then took over the whole front room and started putting up these shelves.
"He used to drive my mother mad. When I went to visit I would notice the collection was just growing and growing. It was crammed in like sardines.
"He did tell me before he died that one day it would all be mine and I asked him what on earth I would do with it.
"I would have loved to have kept them and if I had a big house I would have but I live in the first floor flat and it is just not practical."
The collection has been divided into three lots for the auction, with the 27,000 seven inch singles conservatively estimated at £6,000, the 8,000 12 inch records at £1,500 and 10,000 CDs and cassettes at £600.
The sale takes place on May 21.