The CAA issued a NOTEX in 2009 which addressed this issue, and was subsequently included in the FEH (2010):
The FEH was intended to give alleviation from this rule but only to allow safety checks to be carried out; the alleviation was not intended to permit examiner involvement in the normal course of training.
http://www.caa.co.uk/docs/175/NOTEX1%202009%20_2_.pdf
The same will apply under EASA.
ifitaint...