Longman and Broderip

https://www.britishmuseum.org/research/collection_online/collection_object_details.aspx?objectId=3399490&partId=1&searchText=music*+trade+card&page=2

Viola LOB 392mm  labelled 'Longman & Broderip / No 18 Cheapside / Haymarket / London' (Courtesy of Bromptons Auctioneers)

Stamped on the back beneath the button "Longman Broderip / No. 80 Cheapside / No. 18 Haymarket / London"