Inside the London Bridge branch of Porky’s BBQ grill, you typically hear the same things at lunchtime: workplace chatter, clinking glasses, the background hum of country music, maybe even the odd game of beer pong.

But today there some additional sounds, such as sighs of relief and nervous excitement. They are emitting from the five members of Marmozets.

It is here that the familial band - comprised of three siblings (singer Becca Macintyre, drummer Josh Macintyre and guitarist Sam Macintyre), ...