Over the years Tyson has stolen many things, but most haven’t remained in his possession: either handed over to the Moriarty Mirrors if orders to steal it, discharged afterwards, or returned to their original owner when possible.
Most of the vehicles he’s needed to steal have ended up dismantled for spare parts and the majority of the money has ended up in charity boxes. Until he got Sienna to agree to take it off his hands, Tyson was stuck with a stolen painting and absolutely no idea what he was supposed to do with it.
A (relatively speaking, small) marble statue that Tyson snatched out of spite from a former business associate of the web has been at his Bath warehouse for over two years now. It’s too valuable to sell conventionally and too recognisable for Sienna to take care of for him. It seemed like a good idea at the time, and now Tyson gets the feeling that its smug expression is mocking him.