Veteran cattleman John Henwood first dealt with Gina Rinehart in 2015, but there is a chance their ancestors crossed paths somewhere in the north of Western Australia decades earlier.

Mr Henwood and his wife, Annette, are pastoral industry stalwarts who sold their Fossil Downs station, covering almost 400,000 hectares where the Fitzroy and Margaret Rivers meet, to Mrs Rinehart nearly eight years ago. The sales process attracted two other WA billionaires, Andrew Forrest and Kerry Stokes, but it was Mrs Rinehart who won out.