Got long-window with my original question and posted it in the wrong forum, so here goes again:

If you file for disclosure, asking for everything relevant (like on the ticketcombat form), and receive disclosure, can the prosecution use anything against you in trial that has not been disclosed?

If I've asked for everything relevant, and they've sent me a disclosure package, then haven't they basically said that the extent of what is relevant to my trial that they have is photocopied into that package, and no other evidence exists?

If they've failed to disclose a copy of that certified form saying that I own the vehicle given the licence plate number (this is for a parking ticket where the ticket was placed on the windshield) then can they produce that form at trial?

They can enter into evidence anything that they want, but the stuff that they need to give to you is enough to "make a full answer and defence" to the charge. So yes and no.

They could enter minor, irrelevant stuff without disclosing it, but any relevant, important stuff must be disclosed to you.

That's pretty much what I gathered from searching.

But, if they don't disclose something major, what do I do? Say right then and there that this was never disclosed, or would have I have to get convicted then appeal and then point out I couldn't make a full answer because such and such was not disclosed.

Say it right there and then. Get it recorded so that it is in the transcript, and the failure to disclose the critical evidence now being presented prejudiced your decision and the approach to the trial.

Then ask for it to be excluded.