Along with a cache of documents rescued by the former PA to Jimi Hendrix’s manager, four never-before-heard tapes will be sold at auction in London on 15 November – 54 years after the rock star’s death. The 1968 demos are understood to be versions of ‘Up From The Skies’, ‘Ain’t No Telling’, ‘Little Miss Lover’ and ‘Stone Free’, running for around seven minutes. Per The Guardian, Mark Hochman, music consultant for auctioneer Propstore, said the demos are “very different in sound and length” from better-known versions. Bidders will need to be feeling flush – each demo is expected to fetch hundre…