You should check which Act (and which section of that Act) the charge is under.
'Violent disorder' is an offence under Section 2(1) of the Public Order Act 1986. It's an 'either way' offence, which means that it can be dealt with solely by a Magistrates court or, if the magistrates believe that their sentencing powers might not be strong enough (or, if the defendant elects trial by jury) it can be passed to the Crown Court.
The maximum penalty in a Crown court is 5 years imprisonment.
'Unlawful violence' is likely to be a wording used under Section 3(1) of the same Act, which deals with 'affray'. It's also an 'either way' offence but the maximum penalty is only 3 years imprisonment.
Chris