Online tycoons net the castle with a record £5m price tag

Stephen Leach and his wife Heather Luscombe are making 18th century Seton Castle by the East Lothian coast their home after shelling out a record price for a Scottish country house.

The couple made their fortune by helping some of the high street's biggest names make the leap to the internet.

Tesco, eBay, Starbucks, British Airways, MTV and Sony Eriksson are among the companies who have turned to Leith-based bigmouthmedia.

The pair cashed in last December, ten years after launching their firm, which was named the fastest growing in Scotland last year.

Their four-storey new home, just outside Longniddry, boasts six reception rooms, six bedrooms and an extensive dining-kitchen on the lower ground floor.

The living space in the main building and two adjoining wings together cover more ground than six tennis courts.

The property includes stables, a stables cottage and a coachman's flat, and extensive grounds, including the ruins of a possibly medieval mill.

The country house was one of the last designed by the famous architect Robert Adam in a castle style.

It originally went on the market for 15m two years ago, before selling for the reduced asking price of 5m.

Bigmouthmedia has made its name as one of the most successful and ethical firms in its field.

It specialises in ensuring its clients websites appear at, or near, the top of the list when people use internet search engines.

The company has seen its turnover increase more than fourteen-fold over the past five years to 15m last year.

A company spokesman said: "Many people still see search engine optimisation as a black art but with ten years' experience, we know there is a science to it.

"It is quite complex, but among the things we do is focus on ways of using the correct keywords and phrases across the site in the navigation, links and main content."

The firm now employs 20 people in Edinburgh and has offices in London and Madrid.

Following the sale to Global Media, a German search marketing company, Mr Leach and Ms Luscombe, who until recently lived in Duddingston, reinvested most of their money to become major shareholders in Global Media. However, they also cashed in some of their equity.

In 2005, Bigmouthmedia, which has carried out work for the Scottish Executive, won the Evening News Business Excellence Awards for the best performing business with under 25 employees.

Sales agents Rettie and Co confirmed the Castle had been sold for the asking price of 5m.

Seton Castle was built by Robert Adam in 1790 for William Mackenzie, an Edinburgh writer who was able never to fully enjoy the fruits of Adam's labours.

He died in 1796 having already been forced to surrender his home following questions over the circumstances surrounding the deal he struck to buy the land. Local legend said an elderly woman whom Mackenzie had evicted from her cottage on the estate had placed a curse on him, prophesying that the new castle would never be his family home. The property was bought by the Wemyss family, who remained owners until the castle was bought in 2003 by developer Mary McMillan for 1.3m.

She carried out extensive renovation and refurbishment work before putting the castle on the market for 15m, a price which would have made it Scotland's most expensive home.

Mr Leach and Ms Luscombe were unavailable for comment.