In this episode, Simon and his team visit Toby and his daughter Islay in Pembrokeshire, where Toby has already created some unusual spaces on his campsite but needs help on his latest big idea of turning a sonar hull from a warship into a land-locked submarine.

Without a straight wall or a corner in sight, top carpenter Ian proves his skills at customising furniture for tricky spaces, while interiors queen Zoe takes on the challenge of injecting some warmth and personality into a grey subterranean space.

Simon has some creative ideas on how to make the space both playful and appealing to paying guests, and inspiration comes from a visit to The Hiveaway, a beehive-inspired B&B overlooking the Teifi Valley in West Wales. This curvy off-grid wooden cabin uses honeycomb design on the interiors, and almost everything has either been hand-built by owners Nick and Lauren or reclaimed. Show less