Stanley (Stan) and Grace Sinfield were born in London and moved to Norfolk in 1954.

They worked for ENSA during the war also singing in clubs and for the BBC. Stan and Grace purchased land in Belton, Norfolk and developed Sunfield Caravan Site. Stan became a champion for the local bowls club which needed lavatory facilities but had planning difficulties and he appeared on Esther Rantzen's "That's Life" programme in 1988 prompting press articles such as 'Bowlers Inconvenienced' and 'Belton Bowlers a little flushed as Esther rants on.'

Over many years Stan and Grace raised money for charities. In 1989, adjoining heath land which had been split into small plots went up for sale and Amanda Daniel, their business advisor and friend, recognised the nature conservation potential of the land. It was agreed to create a nature reserve and Stanley began to purchase the plots. With the help of the Norfolk Wildlife Trust and a stalwart band of Norfolk Conservation Volunteers a management plan was agreed and work began to restore the heath. Stan, Grace and Amanda became the founder trustees of The Sinfield Nature Conservation Trust which was registered with the Charity Commissioners in 1994.

Under the Trust's management the heathland became a County Wildlife Site. In 1993 the Sinfield Trust took part in a University of Sussex project to reintroduce the Natterjack toad and a special pond was built on the heath. However the population of Belton grew rapidly and when Stan and Grace retired and moved away it became impossible to protect the nature conservation site. Problems began to occur with habitat damage by public access on foot, motorbikes and in cars. In 2004, at the end of the Countryside Stewardship Scheme the Sinfield trustees felt it would be better for the land to be protected by a local business which was able to prevent inappropriate access while continuing the nature conservation.

Stanley died on 1st May 1999 and Amanda looked after Grace until her death aged 91 on 30th December 2004. The legacy left by Stanley and Grace allowed the Sinfield Trust to purchase White House Farm, Hasketon, Suffolk in 2005. The Trust now has a site which can be protected for future generations.