Most people would have taken one look at the surveyor’s scathing report on the Old Manor House in Knaresborough, North Yorkshire, and simply walked away. The 26-page document listed a catalogue of problems - rising damp, rampant wood beetles, a decaying roof and an archaic heating system - and gave a blunt warning that making it habitable would probably break any estimated budget.

David Rance, 59, a management consultant, was one of those who would not have given it a second glance had it not been for his wife, Jayne, who was “blown away” by the unusual chequered black-and-white medieval house on the banks of the River Nidd.

“It was an emotional reaction,” says Jayne, 54. “As soon as we walked through the gate, I knew it needed saving. It was a wreck, and I know it was madness, but sometimes a house finds you, rather than the other way round.”

David, too, was soon won over, especially when he stepped into the oak-panelled sitting room, dominated by a heavy oak chimney piece believed to have been made in 1661, to commemorate Charles II’s accession to the throne. “Sit down for a moment and tell me what you hear,” he says, relaxing into a large sofa. “Can you hear that? Complete silence. We’re in the middle of town yet it’s utterly peaceful.”

In fact, the entire house is remarkably quiet, considering that one wall supports a road running above it, and that it used to be a restaurant popular with tourists. “The restaurant was closed years ago, but one morning, two old ladies came wandering down the path, walked inside and asked for two cups of tea,” Jayne says. “They seemed quite put out when I told them it was now a private house.”

The Grade II-listed building, which the couple bought 11 years ago, is a Knaresborough landmark. Local history books suggest that in the early 13th century a hunting lodge was built on the site for King John when he travelled north for a few weeks’ sport. It was constructed around a large, rooted oak tree, using its pared-down trunk as the main support and its lower branches as ceiling joists. The main part of the house dates to the early 17th century.

Jayne lifts a latch on a crooked oak door in the dining room wall to reveal the gnarled, squared trunk that still stands in the centre of the house. Stuck to the back of the door is a bill giving notice of Knaresborough Fair on February 16, 1756 – though most of it has been obscured by 20th-century paint and varnish. The top half of the trunk is on the landing, but the tree had to be cut at this point when part of the roof collapsed in the 19th century.

According to G Bernard Wood’s Historic Homes of Yorkshire, published in 1957, James I gave the house to his son, the future Charles I, to use as a fishing lodge. “Something stronger than mere tradition declares that a defeated Charles signed the treaty of capitulation in Cromwell’s presence, in this very house,” Wood wrote. “The spacious Oak Room [now the sitting room] is the most likely room for this episode.”

Wood says that the Old Manor House also contained a bed used by Cromwell, who moved to the house from a property on the high street, where he lodged during the siege of Knaresborough Castle in 1644. The bed was listed in the fixtures and fittings when the Rances were preparing to buy the house, but had gone by the time they moved in. Its whereabouts remain a mystery.

It was clearly in situ when the house was owned and occupied by the Roundells, a prosperous, respected Knaresborough family who remained there until the early 20th century. The checked pattern on the exterior walls is believed to have been painted on by a chess-loving Roundell a century earlier. The house served as a tearoom, guest-house and restaurant until a property developer bought it in the late 1980s and rented it out for several years.

“By the time we came along, it was in a sorry state,” Jayne recalls. “Fortunately, we weren’t looking for the perfect house.” The couple were living in a modern gated development near Windsor Castle when David’s job took them to Jayne’s native Yorkshire in 1996. “We were looking for a house to renovate. I didn’t want to be a bored housewife,” Jayne says.

There has been little chance of that with the Old Manor House. At £235,000, the five-bedroom property, with a large riverside garden, seemed a bargain - until the Rances received the surveyor’s report. Although the house was structurally sound, and the oldest parts had withstood the test of time, later additions had not fared so well.

“We spent a lot of time undoing other people’s mistakes,” Jayne says. “I don’t think the owners in the past century had much respect for the property’s history. We found rubber-backed carpets stuck to the original floorboards and wallpaper over the panelling. The flagstone floor in the dining room had been covered with yachting varnish which had damaged the surface.

“We have pictures of the house, taken in the last century, showing rooms full of ancient furniture – including Cromwell’s bedstead – but all that had gone by the time we bought it.”

Jayne is determined that the house’s remaining “treasures” should be protected – and wants to obtain a preservation order for the 400-year-old mulberry tree in the garden. According to Wood, it was planted at the command of James I to encourage the newly established silk industry, providing food for the silkworms.

“It’s the most amazing tree, which fruits every year - though most of it falls off and gets eaten by the birds,” Jayne says. “I would hate someone to chop it down when we’ve gone.”

The couple, who have a daughter, Bee, 14, have gone to great lengths to restore the original character of the house, sifting through the extensions, alterations and reconstructions that have taken place over the centuries. During the first nine months, Jayne oversaw the demolition of an “unsympathetic” extension; the building of a kitchen extension, using reclaimed stone, roof slates and timbers; the tanking of the original cellar to prevent flood damage and rising damp; replumbing and rewiring hidden behind reclaimed wooden skirting boards; the replacement of rotten windows to match the original mullioned ones; and the cleaning of floors, beams and oak panelling. It has cost them £200,000 – including £48,000 on building work that involved propping the bankside with a concrete platform and balusters before the extension could be built, and £10,000 on creating a medieval garden.

“The garden was unkempt and uninspiring when we bought the house,” Jayne recalls. “I spent a lot of time in the library researching medieval garden designs before the builder came and dug the foundations for the low walls and symmetrical paths. I planted box hedging, rosemary and lavender.”

After having invested so much time, energy and money, the Rances had planned to stay for years. “We thought we’d be leaving here in a box,” says Jayne. But with Bee at boarding school and David’s two older daughters, Elizabeth and Johanna, married with children, they decided to move to something smaller in Knaresborough.

“Everyone thought we were mad to take this on,” Jayne says. “Even the surveyor said, ‘Can’t you find something better than this?’ But I think we’ve restored the building’s integrity and helped to preserve some of its history. We feel like its guardians, and we would like to sell it to people who will look after its past, as well as its future.”

The Old Manor House, in Knaresborough, is for sale for £975,000 with Carter Jonas; 01423 523423, www.carterjonas.co.uk

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