So essentially one of them cracked and admitted it? Or they bragged to someone? I can't understand how they would have otherwise found out about the scheme. It seems as if they just kept tight lipped about it, stuck to their requests being a superstition, they would be fine.
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.
