A couple have transformed a 600-year-old castle they bought for £65,000 into a luxurious home worth £700,000. Janet and John Brennan have spent eight years and hundreds of thousands of pounds turning Barholm Castle, in Dumfries and Galloway, from a ruin into a stylish castle home. They bought the 15th Century fort, reputed to have been used by leader of the Scottish Protestant Reformation John Knox as a hiding place, for just £65,000. Barnholm Castle in Dumfries and Galloway, which has gone on the market for £695,000 after being transformed from old ruins . John and Janet Brennan (right) bought Barnholm Castle (left) for just £65,000 in 1997 and have spent hundreds of thousands of pounds renovating it . But now it is on the market for offers over £695,000 even though at that price the couple will lose a six-figure sum. However, despite that, Janet, 60, and John, 64, insist the project was a 'labour of love' and they have 'no regrets'. The Brennans first stumbled upon the castle near Gatehouse of Fleet - once home to a branch of the powerful McCulloch clan - in 1997 when it was just a shell of crumbling stone walls. It took two years to complete the purchase, four years to get planning permission and three years of restoration. The castle's large living area, pictured, was formerly the great hall in the fortress, which is thought to have once housed Scottish minister John Knox . Barnholm Castle's great vault is now the luxury home's kitchen, which is big enough for a dining table and all modern appliances . One of the four bedrooms in the £700,000 property. The Brennan's bought the fortress in 1997 and spent four years getting planning permission and two years carrying out the renovation . Even though the property is on the market for £695,000, the couple have spent hundreds of thousands restoring the castle meaning they will actually incur a loss . The grade A-listed building was lovingly transformed into a stunning home while staying true to its historical roots. Mrs Brennan, the chairwoman of the Scottish Castles Association, admitted: 'The restoration cost more than the asking price but it was a labour of love - we were not doing it for profit. 'We've no regrets. Other people take up golf and they buy boats. We bought a castle.' The retired university lecturer added: 'It was a massive project. The exterior of the castle during its restoration. Mrs Brennan said they wanted to make a stunning home while keeping the property true to its historical roots . It took two years to fully restore the castle after planning permission was granted. It also has stunning sea views over Wigtown Bay . A decorator paints the ceiling during the castle's restoration. Mrs Brennan says the newly refurbished property would be a fabulous holiday home . 'We were driving and saw a sign on the road saying castle for sale. 'When we drove up the narrow, winding track and saw it we fell in love with it. It was love at first sight. 'We were always interested in castles and visited them over the years. But it was a spur of the moment decision. 'We saved it. It was described as being in a precarious condition.' The castle now has rooms over four floors as well as stunning sea views over Wigtown Bay. The ground floor vaulted chamber has been converted into a kitchen while the great hall has been transformed into a large living space. Four bedrooms are found on the upper floors, including one said to have been used to shelter John Knox. The crumbling ruins of Barholm Castle in Dumfries and Galloway, when it was bought by Mr and Mrs Brennan for £65,000 in 1997 . Mrs Brennan outside the castle shortly after buying it. She described the restoration project as a labour of love . Meanwhile a staircase in the turret leads to upper cap house chamber, with a door to the roof parapet. Mrs Brennan, who has written a book on the subject of restoring castle, added: 'It's an enjoyable experience living in the house. 'It's not that we're selling because we want to leave it - we want to be closer to family. 'I think it would make a fabulous holiday home for someone with deep pockets. 'Or a home for a retired couple who want to live somewhere really special.' John Knox was a Scottish clergyman, who was the leader of the Protestant Reformation in Scotland and often considered the founder of the Presbyterian denomination. He was a Catholic deacon and priest but first joined the movement to reform the Scottish church in the early 1500s. He then went on to teach a number of sons of Protestants who had been captured in St Andrews Castle and called on Knox to become their minister. It was at this time that he is believed to have used Barholm as a place of refuge. In 1547 he was captured by the French, who attacked St Andrews Castle and was kept as a prisoner for over a year. On his release, he travelled to London, where he continued to attack the Roman Catholic faith but left the UK again in 1553 when Mary I became Queen. When he returned to Scotland, he realised how much the teaching of the Reformers was spreading. He then became one of the most well-known preachers in Scotland, with the Scottish Reformation taking place n 1560. Knox is credited with helping to write the Scots Confession of Faith, one of the first formal documents of the Church of Scotland.
Janet and John Brennan bought a crumbling Barholm Castle in Dumfries and Galloway for just £65,000 in 1997.
The couple spent eight years chasing planning permission and spending thousands on renovating the castle.
It has now gone on the market for £700,000 and has four bedrooms as well as sea views over Wigtown Bay.