A couple who painstakingly restored a manor house at the site of an ancient port which helped in the rebuild of Canterbury Cathedral are selling it for £2.5 million.

Patrick Heren and Fiona Cadwallader bought Watergate House in Fordwich in 1999, moving from Clapham with their three young boys.

The Grade II-listed building, which has seven bedrooms and four bathrooms, sits on the River Stour and was previously in control of the lucrative port of Fordwich, which moored boats from Normandy importing Caen stone, used to rebuild the Cathedral in the 11th century after the Norman conquest.

Its garden is at the site of St Augustine's Wharf.

The riverside house was in desperate need of repair and the ambitious project took the couple eight years to complete.

Interior and garden designer Ms Callwallader says it became her life - with her stopping work to see it through.

"As far as I was concerned, I was a custodian of something special," she said.

"It needed rescuing. It was a labour of love."

The property, belonging to St Augustine's Abbey from the Saxon times to 1535, has had many occupants, including John and Gregory Blaxland, who were born and raised in the house before becoming the first non-convict settlers of Australia in 1805.

In 1943 it also featured in the classic Powell and Pressburger film A Canterbury Tale.

Ms Callwallader says it was in an "absolute mess" when they bought it.

"It had leaking roofs, it needed a complete rewire, there was damp, there was a rat in the kitchen," she said.

"To give you an idea of what state it was in, the first night the children were there I got into the bath with them and the tiles round the edge fell into the water. They had just been propped up."

Two-and-half years' work stopped due to dwindling funds, but 'phase two' started a couple of years later, with the restoration eventually completed in 2007.

"It became my life," said Ms Cadwallader. "I was designing it, running it, I made drawings for all the rooms,"

"I'd worked with listed buildings before and this was a rescue job.

"I thought of it as a tardis. Every time we took plaster or panelling off we would find a big void and more space.

"In the drawing room we took off the plaster and found a fireplace and a four foot mound of earth and oyster shells. The house was a soap factory before and it was the remains of workers' lunch, when oysters were cheap and plentiful.

"I also found a medieval archway and a big listed mural, which we restored."

The couple are now downsizing as Ms Callwallader says it is too big for just the two of them.

"It is sad but I was a custodian and I feel I've done a good job of rescuing the house and it's something to be proud of."