Dandelion

These 1975 copies of International Musician and Recording World magazine: http://www.muzines.co.uk/articles/dealer-news/4953 and http://www.muzines.co.uk/articles/dealer-news/5025 suggest it was actually a retailer of musical instruments and equipment where Barclay James Harvest, Be-Bop Deluxe and Billy Fury did their shopping. Still, Dandelion sold copies of the Only a Northern Song compilation tape in 1980, which qualifies it for this as retial music shop.