The following link gives an even earlier date for Jones' patent - Filed 14
Dec 1928, patented Apr 19th 1932. Nice drawings too. 

http://www.irvteibel.com/wp-content/uploads/2016/09/1932-W.-Bartlett-Jones_Stereo-820x1024.png


And just to fill in the gaps - in his book, The Inventor of Stereo: The Life
and Work of Alan Dower Blumlein, Robert Charles Alexander writes, “…on
Friday, 19 January 1934, nine sides were cut of a rehearsal of Mozart's
Symphony No. 41 'The Jupiter', with the London Philharmonic Orchestra,
conducted by Sir Thomas Beecham."