He was born in outback Queensland where his father had moved as a young man from Ireland to work as a jackaroo.
[1][2] His younger sister was Annette Bluebell Dysart Grey (1890–1981), born in Victoria, where the family lived for several years.
Robin's father, Edward George Grey, was born in Dublin, the youngest child of Charles Samuel Grey (1811–60), Paymaster of the Irish Civil Services, and Margaret Dysart Hunter, daughter of General Sir Martin Hunter.
He specialised in agricultural financing, reflective of his upbringing on station properties leased and managed by his father.
In 1940 he presented evidence in Perth to the West Australian Royal Commission on the Financial and Economic Position of the Pastoral Industry in the Leasehold Areas in Western Australia[13] as part of his role as Inspector with the Union Bank of Australia: "Whilst fully recognising the very difficult period the industry is now experiencing, particularly in the Gascoyne and Murchison districts, periods of lean years have occurred in the past and have been overcome.