DJ Semtex looks on as the decks slide across the table. The crowd continues to bounce in front of him, oblivious to any disruption. It’s June 2018, and the veteran selector is playing yet another DJ set, only this time, he’s on a boat, somewhere on the Thames.

“It was a madness,” Semtex recalls. “The decks were moving around, the laptop was going and everybody was getting wavey.”

Semtex speaks quickly and with passion, so Music Week can’t get a ...