The most likely scenario is that at the second casino one of the managers saw the strange winnings, rewound the tapes, and deduced what they were doing with the rotations.

Once that's done, Ms. Sun's criminal record would be easy to track down. Inquiry to figure out what she had in her cell with her.

Then it's a matter of asking them, under oath, to confirm these conclusions. They either have to plead the 5th (which I don't think one can in England) or acknowledge what they did.

A good casino lawyer and investigator could get 90% of this.