There is no such thing as
Theoretical knowledge for the JAR-FCL PPL requires that the applicant passes, amongst other things, the Communications (PPL) written exam. If the applicant wishes to have a FRTOL issued at the same time as the PPL, then the RTF Practical Test must also be passed before the licence application is submitted - the advantage of submitting applications for PPL and FRTOL together being financial.
There is
no requirement, however, to pass the RTF Practical Test before the PPL Skill Test. But sensible people will ensure that they have met FRTOL requirements before flying their 'Q X-C'. The better flying clubs insist on it!