No - that would just mean that you hadn't quite made the required standard for the JAR-FCL PPL. But it should really only be a formality to appease the JAA; no lower standards are accepted for the NPPL NST and GST than for the JAR-FCL PPL Skill Test. It's just that there are a few extra items to cover for the JAR test (e.g. position fixing by use of radio navigation aids). You should find it an utter breeze!