Working long days in a factory in Guangdong Province in China, her evenings spent alone in a purpose-built flat in the dormitory town of Zhuhai, it was not surprising that Katherine Sheers was feeling homesick for her native Welsh Black Mountains. ''I had a fabulous job, designing lingerie, and I was working with the world’s leading brands, travelling to New York every few months, but, I don’t know, just one night, I felt really quite down. Which is not like me at all,’’ she says.

In that moment, through a quirk of fate – not to mention the quirks of Facebook – Katherine, now 35, turned her life on its head. ''I decided to cheer myself up by looking at pictures of the Skirrid, my favourite mountain back home in Abergavenny where I grew up.’’ That casual surfing of the internet was the catalyst for a cascade of events which has led her, in less than three years, to the elegantly renovated Welsh cottage where she now lives, complete with gorgeous baby girl, celebrated poet/playwright husband, and her first book – a guide to creating your own luxury lingerie.

Katherine, who is sleek and stylish as a Manhattan cocktail, but warm and friendly as a Pice bach fresh off the griddle, still can’t believe her personal good fortune at times. Yet, there’s no doubt her success, professionally and personally, are rooted in her tremendous capacity for hard work, her taste for adventure and a passion for the place of her birth. The daughter of consultant radiologist in foetal medicine and a nurse (her mum still works on the gynaecology ward at Abergavenny hospital) Katherine grew up with younger brother Tom living an outdoors, rural childhood, building dens and floating rafts.

''I was definitely a tomboy, but when the weather was bad, I learned how to entertain myself indoors. And I found a passion for making clothes for dolls, with Gran teaching me embroidery and needlework.’’

After school, Katherine decided to specialise in textiles and began a degree course at Chelsea School of Art because ''I couldn’t wait for the bright lights of London’’. She supported herself with part time work, including hand beading knickers sold in the upmarket store Liberty at Oxford Circus, something she describes as a ''pleasing intricate’’ task.

Then as part of an exchange programme, she moved to New York where she took a class in foundation design and lingerie construction and so found her calling. ''It made immediate sense to me. I could see a pattern in 2D and understand instantly how it should look, fit and feel in 3D.’’ Back home, she transferred to De Montfort University Leicester to do a degree in lingerie design and took her second and third year simultaneously, leaving with a First in 2005.

Her first job was working for a celebrity (sadly, she discreetly declines to name them) who had launched a brand of lingerie, as part designer, part general factotum. But London soon palled and next stop was Sri Lanka. ''I got itchy feet, and was offered a job there as design manager for a knicker elastic supplier. It was a fantastic experience: I was learning Singhalese and living in tiny village an hour from Colombo.’’

Moving on again, Katherine freelanced as a designer as she clocked up a few months each in Istanbul, Marrakech, and Brazil before accepting a job from the Chinese suppliers to the global lingerie empire that is Victoria’s Secret, a post which enabled frequent travel to New York, a city she felt increasingly at home in.

Yet, none of these journeys was to prove as incredible as that from globe-trotting lingerie-ista to new mum in Wales.

''Working in Guangdong was an extraordinary experience, but all the factory cities are built purely to accommodate workers, mainly itinerant migrants from the north, who just want to work as many hours as they can to send money home. After work, there really is nothing to do, no theatres or galleries or cinemas. For the first time, in years of travelling, I really missed Wales. So that night I logged on to the internet.’’

Here, she found pictures of her favourite landscape, The Skirrid or Holy Mountain in Brecon Beacons: ''The Skirrid was my mountain; I used to climb up it every Sunday when I wanted to have a 'think’ as a teenager.’’ But she also found poems, too. It turned out someone else thought of the mountain as ''theirs’’.

'’I saw the poetry was written by someone called Owen Sheers, a name which rang a bell. Then I remembered there had been a boy of that name about five years ahead of me at our comprehensive school, King Henry VIII. But all I could recall was that that Owen had been a sort of good looking rugby player, not a poet.’’ Sheers, now 40, was indeed a poet/playwright and novelist. His second collection of poetry, Skirrid Hill, had won the Somerset Maugham Award in 2006. Katherine found herself so moved by it that via Facebook she sent him a message: ''Thank you for a hit of home – that was just what I needed.’’

The two struck up a Facebook friendship, and discovered they had more in common than Skirrid. ''We’d both travelled a lot; we were Welsh wanderers but rooted in Abergavenny,’’ she explains. Owen had been born in Fiji, and also lived in New York. Come Christmas 2011, both planned to be in Abergavenny for Christmas. ''We decided to meet up; but not in a pub. We thought, let’s meet on the Skirrid on Boxing Day at 4pm.’’

So, in the semi-dark of winter, Katherine and Owen got their first glimpse of each other by wind-up torchlight. Although they nearly didn’t. Owen was waiting on ''his’’ side of the mountain. Katherine was on ''her’’ side. ''I was about to give up when I got a text – there’s not much reception normally, either – saying, 'Where are you?’ Luckily, we found each other.’’ She means spiritually, too.

^{Katherine, pictured with her husband, the poet and playwright Owen Sheers}

Shortly after Katherine returned to China, and Owen to London, where he was working on The Two Worlds of Charlie F, a play based on the experiences of soldiers wounded in Afghanistan, but the couple embarked on an intense long-distance relationship. ''You just know when it’s right,’’ shrugs Katherine, smiling.

Six months later, she left China to move in with Owen - and to start sewing again. ''In China, it was all mass manufacture; I was missing the 'hands on’ making element.’’ She had also been discussing the idea for a book with Laura Stanford, an old friend from de Montfort, who is herself a successful lingerie designer, working with Agent Provocateur, and who now runs a bespoke luxury atelier called Of Life and Lust.

''So many women would ask where they could get the perfect lingerie for them, and we’d find ourselves saying, 'Oh, I can teach you that’. This coincided with a surge of interest in home sewing and so Laura and I developed the concept for our book The Secrets of Sewing Lingerie.

That Christmas - 2012 - Katherine took another romantic walk up the Skirrid with Owen on Boxing Day, a year after they had first met and came down the mountain with an engagement ring.

''Well, we slid down actually, on our bottoms; it was very muddy.’’ They were married in Booth’s bookshop, Hay on Wye, the following summer, followed by a second ceremony in the south of France. Katherine wore a garter made of French lace by Laura.

Moving back to Wales seemed inevitable and the couple spent a year renovating their cottage, with the central heating installed just in time for the arrival of baby Anwyn, who - as if this story could be any more perfect - was delivered by Owen in front of the log burner. Katherine and Laura’s book was not far behind. No wonder the designer looks like she still can’t believe her luck – although that doesn’t mean she intends to slow down. ''I’m so proud of Owen, he works so hard. And I love being a mummy, and I’m working on plans for another two books, oh and I’m starting a blog,’’ she says excitedly.

Much like one of her intricate and beautiful undergarments, Katherine Sheers's new life seems to be perfectly gathered but held together by impeccable but invisible seams.

The Secrets of Sewing Lingerie: Making Your Own Divine Knickers, Bras & Camisoles by Katherine Sheers and Laura Stanford is out now. Katherine and Laura will be running workshops around the UK starting Spring 2015; for details, visit thesecretsofsewinglingerie.com