Gronow-Davis was an established artist and held bi-annual exhibitions. He and his partner Pitt-Rivers were both collectors of art, especially Asian works of art. After his death in 2016, Gronow-Davis's art collection was auctioned by Duke's of Dorchester.
Gronow-Davis was the partner of Michael Pitt-Rivers, conservationist and owner of the Rushmore Estate, and moved to King John’s House, near the estate at Tollard Royal, Wiltshire in 1961. Their relationship began after Pitt-Rovers' marriage ended in 1965. When Pitt-Rivers died in 1999, the Trust which runs the estate was inherited by Gronow-Davis.
The Rushmore Estate had been in the Pitt-Rivers family for generations and includes the Larmer Tree Gardens pleasure grounds.
In 2009 Gronow-Davis built a 65ft folly, the tallest folly to be built in England in more than 100 years.
At his death, on 20 September 2015, the Larmer Tree Gardens estate was valued £50 million.
- "Millionaire builds 65ft folly on estate". The Telegraph. 8 July 2009. ISSN 0307-1235. Retrieved 26 July 2020.
- William Gronow Davis: New Paintings. Hambledon Gallery. 1972. Retrieved 4 October 2017.
- Hogger, Harry (29 January 2016). "Art collection of William Gronow-Davis to feature in Duke's auction". Retrieved 4 October 2017.
- Walker, Tim (23 September 2014). "William Fox-Pitt races to court over capital distribution at Rushmore Estate". The Telegraph. ISSN 0307-1235. Retrieved 4 August 2020.
- O'Sullivan, Jack (8 August 1998), "Outdoors: The thrill of the Chase", The Independent.