The man reported being approached by two women at the Cattle Market car boot sale on Sunday (July 18) at about 11am,
The pair had claimed to be charity collectors before engaging with the man and touching his arms and body. He later realised that his watch, which is estimated to be worth about £10,000, was missing.
The first suspect is described as a white woman with a tan, around 22 years old, 5’8” and wearing a light blue coat. The second is a white woman with a tan, around a similar age and 5’6”.
Police are urging members of the public to be vigilant as detectives continue to investigate reports of similar incidents in the West Sussex area.
Detective sergeant Vicky Guy said: “We understand that reports such as these may cause concern among local communities and we are investigating these incidents as a priority.
“Please be vigilant if approached by strangers who attempt to distract you and report any suspicious behaviour to us so we can take action.”
Anyone who may have seen two women with clipboards, has dash-cam footage from either incident or information that could help with the investigation, is asked to report it to police online or by calling 101, quoting Operation Overdrive.