It is a JAA requirement.
However, Progress Checks and Safety Checks flown by a UK FE/PPL on a student do not disbar the same FE from conducting the PPL Skill Test with that student.
This ruling does not apply to the NPPL (although it is recommended) nor to the IMC Rating as both are non-JAA.
Radio 'navigation' is not really part of the PPL Skill Test apart from fixing position by use of navigation aids and also a short 'radial' tracking requirement. Some FEs, however, seem to be demanding considerably harder radio navigation work which is contrary to the whole spirit of the requirement. See the article in the supplement to the latest
Pilot for an example.....
For those who don't know, the CAA Standards Document 19A
http://www.caa.co.uk/application.asp...detail&id=1206 provides a fair bit of information for PPL Skill Test applicants.