I agree with both destructor and BEagle that the flight is a one hour instructional flight and not a test therefore it is totally permissible to instruct during the flight provided that by the end of the flight the candidate achieves a suitable standard.
I disagree with BEagle where he states that he would refuse to sign if he had to take control. Whilst that is absolutely true during a test and may well apply during the one hour instructional flight it is not necessarily the case in the one hour instructional flight.
Scenario – Candidate totally fouls up a spiral dive recovery and I have to take control. Following some instruction he/she performs a number of perfect recoveries. The rest of the flight is to an acceptable standard. I would sign his/her logbook.
In the above scenario had I been conducting a flight test the candidate would have failed the spiral dive recovery, which marks the major difference between the one hour instructional flight and a skill test.
I also agree with BEagle that the recommended content of the one hour instructional flight is a load of rubbish. I have some items that I include in most one hour instructional flights/club checkouts but I also always ask the candidate it there are any items which they would like to include in the flight. A large number of candidates reply “ Could we include XYZ since I have not practiced that recently”. Much better to spend some time doing XYZ than slavishly following the recommended content for the flight.