Even by the standards of the privileged classes in Edwardian England, the large Georgian mansion overlooking the River Ouse would have made a handsome wedding present.

It was gifted to the heiress and racehorse breeder Enid Edith Scudamore-Stanhope by her father when at 21, she married the 46-year-old Edwyn, 10th Earl of Chesterfield. In the 1920s they ran a stud farm there.

They were the last private owners of Beningbrough Hall, which has been in the care of the National Trust since the Government accepted it in lieu of death duties, 60 years ago. However, its past life is coming back to haunt it this week,  with visitors invited to watch the Earl’s portrait being touched up.

The intricate process of de-framing, cleaning, re-touching the gilding and re-framing the painting is taking take place in public over three days until tomorrow.

Francis Downing a fine art conservator working on a 1890 portrait of The Tenth Earl of Chesterfield the final owner of Beningbrough Hall.

At the same time, in what the curators are calling a “horticultural tombola”, plants from the elaborate Italian borders in Beningbrough’s grounds are being cleared and offered to guests in return for a small donation.

The eight-acre garden boasts labyrinth paths, hidden woods and a working walled kitchen garden, as well as a sunken wall known as a ha-ha, which prevents sheep and cattle entering the Hall.

The 300-year-old grounds are the subject of a “reinvention” by garden designer Andy Sturgeon, who is introducing Mediterranean designs as part of a “long term design vision”.

Sam Shipman, head gardener at Beningbrough, said: “It’s exciting to be preparing for the next phase for the gardens and to be able to involve visitors.”

Earl gets back in picture as Beningbrough Hall restores a portrait of the past