Conversation so far:
What happened with the band Iron Maiden in New Year's Eve 1978?
On New Year's Eve 1978, Iron Maiden recorded a demo, consisting of four songs, at Spaceward Studios in Cambridge.
What happened to the band Iron Maiden's demo?
The band Iron Maiden presented a copy to Neal Kay, then managing a heavy metal club called Bandwagon Heavy Metal Soundhouse, located in Kingsbury Circle, northwest London.
What did Neal Kay do after listening to the band Iron Maiden's demo?
Upon hearing the Iron Maiden's demo tape, Neal Kay began playing the demo regularly at the Bandwagon, and Prowler, eventually went to No. 1 in the Soundhouse charts.

Question: did they start to become popular?
Self-contained rewrite: Did the band Iron Maiden start to become popular after Neal Kay started playing their demo tape at the Bandwagon?