Tollefsen

I found this advert in the 'Hammersmith & Shepherds Bush Gazette' dated 13th December 1957: “Famous Guitarist BERT WEEDON will demonstrate the Guitar and Autograph his records at TOLLEFSEN, 3, WOOD LANE, SHEPHERDS BUSH, W.12, on SATURDAY, 14th DECEMBER at 4 p.m.”

There is an interview with Toralf Tollefsen's daughter that mentions the music shop in Shepherds Bush (Tollefsen & Neilsen) at this link:
https://www.accordions.com/articles/tollefsen.aspx

I found this advert in the 'West London Observer' dated 16th December 1955: “ACCORDION FOR XMAS? WONDERFUL IDEA! BUT - don't get wrapped up with glorified rubbish. Come to TOLLEFSEN & NEILSEN, 3 WOOD LANE, Shepherds Bush Green. The dealers who PLAY AND UNDERSTAND the accordion. Part exchange. Hire Purchase, all instruments.”
... and this in the 1st November 1957 edition:
“RECORDS, GUITARS, ACCORDIONS at Tollefsens, 3 WOOD LANE, SHEPHERDS BUSH GREEN. Tel: SHE 4642. We are SPECIALISTS! VISIT OUR NEW SHOWROOMS.”