The Bass Cellar moved around between No. 21 and 23. It was here that Coldplay’s Guy Berryman bought his first bass guitar when he was starting his music career.

For sci-fi fans: the famous comic and science-fiction bookshop Forbidden Planet was established here at No. 23 in 1978 before moving to New Oxford Street and becoming an international chain. Rumor has it that when Douglas Adams attempted to attend a signing for the first The Hitch-Hiker's Guide to the Galaxy book in October 1979, the queue to the shop was so long that Adams thought a demonstration was taking place elsewhere.

Sources: Wikipedia, https://www.chateaudenmark.com/journal/no-21-25-across-time