It’s a blustery morning at Fremantle’s Booyembara Park. Rain hammers down in sideways sheets, and the horizon is a blurred smudge of green and grey. Hardly ideal conditions to interview author Craig Silvey; we can barely hear each other over the downpour.

“Lovely day for a walk!” Silvey shouts from beneath his polka-dot umbrella. He points to his sodden shoes with a grin. “I’m squelching. Should’ve worn some gumboots … we’re like Shackleton out here,” he laughs.On sunnier days at “Boo Park”, as Silvey calls it, the 43-year-old and his partner, Clare Testoni, stroll the lake with their four-month-old twins, Hazel and Stella, while their three-year-old daughter, Matilda, hoons around on her push-bike.‘I am stubbornly determined, dedicated and patient in my approach to storytelling’ … Silvey at Booyeembara Park. Photograph: Tace Stevens/The Guardian“We have a rapidly expanded family,” Silvey says, sheltering beneath a corridor of paperbarks. “It’s extraordinary. Our hearts are full. I’m a very devoted and besotted father.”

More than 15 years after the publication of Jasper Jones, the modern Australian classic which won readers around the world, Silvey seems happily anchored in a gentler chapter of life. He’s weeks away from launching Runt and the Diabolical Dognapping, the sequel to his bestselling children’s novel and feature film Runt.