We haven't seen any of the evidence you intend to rely on, but it's worth remembering that defending your current civil case is likely to be easier than demonstrating fraud. To defend your case, you simply need to establish that, on the balance of probabilities, Alliance have not adequately proven that the driver failed to display a ticket.
To demonstrate fraud there would likely be a need to demonstrate intent, which would involve proving that a ticket was displayed (this is not necessarily the same as showing that Alliance have failed to prove that one wasn't displayed), and proving that the warden knew a ticket was displayed but produced evidence that deliberately hid this fact.
We haven't seen your evidence, so you might already have covered all of this of course.
