Millie Sparrow and Matthew Lister invested all their savings and months of work into the new venture
Megan Shaw Senior Lifestyle Reporter
04:00, 06 May 2026
A Yorkshire couple have turned an old horsebox into a wood-fired sauna with sweeping views across Wharfe Valley.
Millie Sparrow, 25, a food product developer from East Morton, and Matthew Lister, 26, a commercial consultant for start-ups from Otley, poured their savings and seven months of weekend work into the venture, which is now up and running just above the town.
Millie had been living in Newcastle after university, where she spent weekends wild swimming and visiting beachside saunas. The couple met on Hinge in May 2025 and within months had committed to what they describe as a “mad idea”.
By August, they were all in. “What started as a Hinge match quickly turned into something a little hotter,” they quipped.
Asked how the idea came about, Millie explained: “I really missed doing contrast therapy whilst being immersed in nature in this way, so I thought, why not bring it home to Yorkshire. My dad peer pressured us into buying a trailer and said, ‘don’t come back until you’ve bought a horse box’.”
Matthew said: “It was Millie’s fault really, she is a keen wild swimmer and loved going out to the seaside and enjoying the gorgeous woodfired saunas on the beach, and swimming in the North Sea afterwards. “Once Millie decided to come back home to Yorkshire when her dad was poorly, we both decided that this would be a something totally missing in-land and that we have the perfect surroundings to build and launch something ourselves.”
They paid £3,600 for the horsebox and spent more than £25,000 on materials, doing all the work themselves with help from family. The build took seven months of spare weekends alongside their full time jobs. Neither had taken on a project like it before. Millie said: “We’ve both been brought up by hands on families, but never done a full conversion to this extent, we really strived for perfection and to make it authentic to the highest Finnish sauna standards.
“We have definitely learned a lot about each other and ourselves, and working on the trailer for the past 8 months has definitely brought us closer together. We, so far, haven’t fallen out too much, apart from once – (we’ll gloss over that haha), but we are trying to make enough time for ourselves and separate work from personal life as much as we can. “We have both converted the horse box in the last 7 months on our spare weekends, whilst keeping up with our day jobs. We’re both passionate about our careers and want to build something sustainable and fulfilling. We’re definitely keen to grow the brand and open up more locations as soon as it makes sense to. Who knows what the future holds!”
Matthew added: “We wanted the best starting point, but when we got into it, one side was rotten and everything needed rewiring. There were moments of doubt, we’d play ‘how long’ and giggle to ourselves but we kept going with lots of Yorkshire Tea for me and Earl Grey for Millie, along with home cooking from Millie’s mum. Our family and friends have been so supportive and are excited to watch us grow!”
The finished sauna now sits on a south facing plot above Otley, with views towards the Chevin and Ilkley Moor. Visitors can expect cold plunge facilities, a wild shower, a bell tent, deck chairs and even a few animals.
Millie said: “There’s something so natural and raw and ancestral about it. You just can’t beat it, it also means we can be totally off grid and mobile. Of course there has been a few bumps in the road, the goats like to scratch their horns against the trailer and knocked our lights off and chewed through the festoon lights – so now it’s fenced in!”
Despite only opening two weeks ago, the response has been strong. They said: “We even have some regulars already, seeing people come back and bring their friends and family is the most satisfying thing. The project has been a huge leap of faith, we’ve put all our savings into it, but we believed in it and now it’s finally starting to pay off.”
Looking ahead, they hope to expand and eventually open more locations. They said: “We just want to create somewhere people can come, relax and take a break from day to day life.”
Asked their advice to others thinking of doing something similar, Matt said: “Bite off more than you can chew, and then learn to chew.”
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