A reward of up to £100,000 ($124,000) has been offered for the return of a solid gold toilet stolen from a UK stately home, as police release CCTV images of a vehicle they believe was involved in the September theft. The fully functioning toilet is a piece of art made entirely from 18-carat-gold that was installed in Blenheim Palace, in Oxfordshire, England, as part of an exhibition by Italian artist Maurizio Cattelan titled "Victory is Not an Option," which opened to the public on September 12. Former UK prime minister Winston Churchill was born at Blenheim Palace, which is now a tourist attraction. Philip Austin from Fine Art Specie Adjusters (FASA), the palace's insurance company, told CNN that a reward of up to £100,000 would be paid if specific conditions are met. First the item must be safely returned, and second there must have been an arrest as part of the investigation. "We have to be very careful that we don't pay the villains," he said. Thames Valley Police say the navy blue Volkswagen Golf R has not been found, according to a statement released Wednesday. They believe it had cloned plates at the time of the theft, which was reported at 4:57 AM on September 14. Police said a 66-year-old man was arrested on suspicion of burglary before being released on bail, and a 35-year-old man was arrested on suspicion of conspiracy to burgle and has been released under investigation. They have previously referred to a "group of offenders" being behind the theft of the toilet, which has yet to be recovered. Police believe the thieves used at least two vehicles during the theft. No injuries were reported as a result of the offense. "I would like to appeal to anyone who was in Woodstock at the time of the burglary that may recognize this vehicle to get in touch with police," said investigating officer Detective Inspector Steven Jones. "The stolen artwork has not been recovered, but officers are working to retrieve it. Anyone who has any information regarding its whereabouts is asked to get in touch with police." Solid gold toilet to land in English stately home The artwork, which is named "America," is valued at around $6 million, according to Dominic Hare, CEO of Blenheim Palace. Police have revealed that insurers are offering a "substantial reward" for the return of the artwork. In an August interview with the Times, Edward Spencer-Churchill, the current Duke of Marlborough's half-brother and founder of the Blenheim Art Foundation, dismissed the possibility that the toilet could be stolen. Blenheim Palace  "It's not going to be the easiest thing to nick," Spencer-Churchill said. "Firstly, it's plumbed in and secondly, a potential thief will have no idea who last used the toilet or what they ate. So no, I don't plan to be guarding it." "America" first went on display at the Guggenheim in New York City in 2016. It made headlines again in 2017, after US President Donald Trump's White House emailed the Guggenheim asking to borrow Vincent Van Gogh's 1888 painting "Landscape with Snow"; instead, the institution's curator offered the gold toilet. Cattelan has previously described the thieves as "great performers." He said at the time: "When this morning I was informed about the robbery I thought it was a prank and it took me a while, after a few checks, to come to the conclusion that it was true and it wasn't a surreal movie where instead of the jewels of the crown, the thieves went away with a b***** toilet," he said in a statement. "I always liked heist movies and finally I'm in one of them." In a direct plea to the thieves, he added: "Dear thieves, please, if you are reading this, let me know how much you like the piece and how it feels to pee on gold."