Although this Wikipedia link mainly refers to a procedure which has now been abolished in England ('committal'), the section under 'England' rather neatly summarises what currently happens:
http://en.wikipedia.org/wiki/Committal_procedure
>>>Can evidence be disputed before a trial begins, does the Judge have the final say on the evidence to be used in the trial.
Evidence, per se, can't be disputed but the admissibility of certain evidence can be challenged. For example, the prosecution can seek to introduce 'propensity' evidence, detailing the defendant's previous convictions and the defence can seek to show that the application doesn't meet the criteria for such evidence being admitted.
>>>does the Judge have the final say on the evidence to be used in the trial
Obviously (because there's nobody else there who can make such a decision).
Useful links:
http://www.app.college.police.uk/app-content/prosecution-and-case-management/hearing-and-trial-management/#substantive-probative-value
http://www.cps.gov.uk/legal/a_to_c/bad_character_evidence/
(There's also a great deal more on that website which might help you to understand the judicial process).