Regent Sound and the Rolling Stones
A vast number of successful 60’s and 70’s bands started their recording careers at Regent Sound. From demos to singles and full albums, these include (besides The Rolling Stones), The Jimi Hendrix Experience (cutting some rough demos and rehearsing), The Kinks (early demos), The Who (part of ‘A Quick One’), Elton John (playing sessions), The Lower Third with David Bowie (demos), Black Sabbath’s first two albums and early albums and singles from The Bee Gees, The Troggs, Slade, Tom Jones, Sandie Shaw, The Equals, John Martyn, Davy Graham, The Yardbirds, The Amen Corner, Herman's Hermits, Brian Poole and the Tremolos, The Downliners sect, Mott The Hoople and countless others. The Eagles rehearsed sessions for ‘on the Border’ (Recorded at Olympic) here.
Sources: Wikipedia, https://www.regentsounds.com, https://www.classicrocktourlondon.com/, http://www.peermusic.uk/