I can't possibly know what the Queen told anyone, Piano, but I definitely believe her influence would stretch to quashing a case she didn't wish to be brought in her courts
TBF Joe's correct that the burden of proof is different in civil as opposed to criminal cases, but if people like us are aware of this I imagine the Mail's extensive legal team are too
Personally I think this will be settled out of court with everyone sworn to secrecy about the outcome, but as a PP asked, "what if they don't?"