No problem so long as you are supervised by a nominated FI.
OK, that's what I suspected. I believe it has been mentioned on here before that this is one situation where a CRI would have an advantage as they have no requirement to be supervised. When you say "nominated", is this referring to the supervising instructor(s) notified at a RTF, or simply an (unresticted) instructor with who agrees to supervise the flight?
What level of supervision is actually required, and what is acceptable?
TrainingCom 1/2007 offers advice for "best practice", but since the only documents with any legal standing (JAR-FCL, ANO) don't actually specify what supervision entails it appears that there is still massive room for interpretation (as an experiment ask a handful of FIs what they think constitutes supervision, then sit back and admire the rainbow of responses you receive
)