There is no level restriction on your licence.
However while most of European airspace above FL195 is class C, they have invented a rule saying that you can't fly under VFR in the clss c above this level.
Other places have different rules. For example in the USA most airspace above 18000ft is class A, in which you can't fly VFR.
In an Irish registered aircraft, you need an IR to be able to fly under VFR, even in VMC.
dp