When Sarah Fortescue first set eyes on Boconnoc House as a 12-year-old, she felt an overwhelming sense of sadness. "The memory's very vivid … I could almost feel the strain from years of neglect," says Fortescue, whose family has owned the Grade II-listed property since 1834. Hidden amongst lush gardens in the Cornwall countryside on Britain's south-west coast, the 18th-century stately home was in a state of disrepair, having been left untouched for 30 years.

But in 1997 her parents, Anthony and Elizabeth, came to its rescue, embarking on a massive restoration which would continue for the next 10 years. Work focused on the main ground-floor rooms, including the drawing room, library, dining room and king's bedroom, and in particular the painted staircase influenced by neo-classical architect, Sir John Soane. The hard work paid off; the project won the 2012 Historic Houses Association/Sotheby's Restoration Award. It has also been shortlisted for the 2012 Georgian Group Architectural Award.

Fortescue was working for Condé Nast House & Garden in South Africa, when she returned in 2011 to work on the interior of Boconnoc House.

"It was one of the greatest and most complex jobs I could have dreamt of, being a Grade-II listed building and hundreds of years old. The home's history and its ancestors played an important role in the design alongside a Cornish workforce of electricians, plumbers, painters, wall paperers, plasters, upholsterers, curtain makers and a Frenchman who danced in, spending a week putting a pink toile de jouy fabric on the bedroom walls.

"As a family we wanted to keep the traditional feel but give it an inviting warmth. To walk into a room and feel excited is my aim. I wanted each room to have its own unique flare … The floor boards are ancient and over time have risen in places and dipped in others. It's all part of the immense character of Boconnoc House. As a child I remember feeling my way around the house, treading delicately on floorboards, winding my way up to the attic, even more cautiously with the floors creaking below and bats flying around. The walls were firm but everything else was derelict."

And if only those firm walls could talk and share some of the stories of its colourful past. It was where King Charles I hid during the English civil war; was purchased in 1717 by Thomas Pitt with the proceeds of the famous Pitt Diamond (the rock was later sold to the regent of France where it ended up in the hilt of Napoleon's sword); has been home to two British prime ministers, and was occupied by American troops during the second world war. Today, the house, gardens and deer park play a calmer commercial role, available for hire for weddings, private parties and corporate events.

"It's an ideal destination for tourists seeking a quintessentially British experience. It has magical parkland of ancient oak woodlands, home to a herd of 120 fallow deer, with the river Lerryn flowing through its deep central valleys, and a cricket green. The house sleeps 16 and a further 12 in surrounding cottages, with supplies of local produce coming from neighbouring farms and dairies. The newly restored ancient wine cellar is in a league of its own and will appeal to our Asian guests," says Fortescue.

But for now, Cornwall is a far cry from bustling Hong Kong that Fortescue now calls home and where she recently set up her firm, Let's Keep it Tropical Designs. "Hong Kong is a treasure chest of ideas and excitement and with China next door there is endless opportunity to create and design, which fascinates me."

For her most recent project, Fortescue worked alongside Tim Shepherd, the creative director of Three Wise Monkeys, on Honi Honi, a Polynesian cocktail lounge that opened last month. "It's been a blast. It's in a great location with one of the city's most attractive roof terraces."

Historical country homes, residential properties and Kiki-style bars - there seems no limit to Fortescue's creative abilities.