Presuming you hold a JAA PPL and are undertaking JAA CPL / IR.
In order to obtain a JAA Night Qualification (NOT Night Rating as no test or revalidation required) you need to fly 5 hours at night, 3 hours of which must be dual, one hour solo cross country and 5 x solo take offs and full stop landings.
If you do not hold this before commencing the CPL course then 5 hours of the CPL must be as above.
As said by BB, there is no such thing as VFR at night in the UK; all night flight is under IFR, whether in VMC or IMC.
HTH
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Edited to add: if you don't already hold a PPL you can do the Night Qualfication as part of your JAA PPL course although the probability is that this will be an extra 5 hours to the minimum 45 hours.