Despite damage to the building, the centre has quickly reopened and the forthcoming auction programme (including a sale of Asian art on November 5) remains unaffected.
In the early hours of Saturday, October 24, a gang of three men used a stolen Caterpillar forklift truck to break down a wall and gain access to the premises.
Tom Keane, who owns The Swan with business partner James Wang, told ATG the offenders had been trying to access the safe but had succeeded only in causing significant structural damage to a Grade II listed property and smashing display cases and their contents. He said the damage to stock would run to thousands of pounds but it was still unclear if anything had actually been taken.
Investigating officer PC Jason Walsh, from Didcot Local CID, added: "The offenders knew what they were doing and went to extreme lengths to enter the building at all costs. At the moment it is unknown what property was stolen in this incident due to the amount of damage caused and debris left behind."
The centre, with a restaurant and bar, has stock of 80 traders and stages regular auctions as Swann Fine Art. Although areas of the property remain a crime scene, it reopened on October 27.
There will be a sale of unredeemed pawnshop pledges together with other art and antiques this Thursday (November 5) followed by a 233-lot Asian art catalogue on November 16.
The latest incident follows another raid at the centre last December where a Land Rover was used to break into the premises before thieves made off with stock valued at an estimated £150,000. Again the safe had been the primary target of the raid.
Anyone with information should call the 24-hour Thames Valley Police enquiry centre on 101 or contact the independent charity Crimestoppers anonymously on 0800 555 111.