I found this piece in 'The Graphic' dated 19th November 1927: “AUTOGRAPH HUNTING UP-TO-DATE Messrs. Layton and Johnstone, the celebrated American duettists, autographing Columbia records in the Regent Street offices of Columbia Salons Ltd. A large crowd of autograph hunters found the occasion too good to miss.”
... and this advert in 'The Era' dated 11th December 1929: “FOREIGN TANGO RECORDS - WE Hold large stocks of the newest and best Tangos, recorded in Paris, Buenos Aires and Madrid, which are not obtainable on any British catalogue. Write for our special Tango List (EA12), Columbia Salons, Ltd., 233, Regent St., W.1. Phone: Mayfair 1785. Open till 7 p.m.”
... and this advert in 'The Era' dated 11th December 1929: “FOREIGN TANGO RECORDS - WE Hold large stocks of the newest and best Tangos, recorded in Paris, Buenos Aires and Madrid, which are not obtainable on any British catalogue. Write for our special Tango List (EA12), Columbia Salons, Ltd., 233, Regent St., W.1. Phone: Mayfair 1785. Open till 7 p.m.”