IIRC it was 15-20 in Songkick's original offices at the back of Spitalfields market (although physical size wise it was probably about the size of a living room

IIRC it was 15-20 in Songkick's original offices at the back of Spitalfields market (although physical size wise it was probably about the size of a living room), it frequently over-flowed into the corridor. They used to make everyone introduce themselves at the start, modern HN meetups lack that sense of intimacy :)