Not an examiner, but a CPL instructor, so I hope my answers help. However, I should point out that the best person to speak to about these questions will be
your CPL instructor, and if your CPL instructor says anything which contradicts what I write here, then take his word, not mine (or at least ask for further clarification from him).
Does the CPL Exam have to be carried out in VFR if not IMC or IFR rated
Yes, the exam is to be carried out VFR (or very unusually SVFR) whatever qualifications you hold.
what are the procedures to follow if during an exam the conditions deteriorate below VFR (say outside controlled airspace and VIS is less than 5km below FL100)
Forget the subject of exams for a minute. What would you do for any VFR flight at any point in your flying career?
First of all, you should make a sensible weather decision based on all the information available on the day. Hopefully, that will prevent you from encountering weather which is not VMC. However, we all know that forecasters get it wrong from time to time, and if you encounter deteriorating weather, you should take whatever action is appropriate
before it becomes IMC, e.g. by making a diversion, or returning to your home airfield.
What the examiner is looking for on the test is that you make exactly the same decisions as you would for any other flight. He wants to know that you will operate the aircraft safely when he is
not sitting there, so you should not do anything different to what you would do on any other VFR flight. Make a weather decision based on the forecasts and actuals available. If you encounter deteriorating weather, turn back or divert before it becomes IMC.
Does the student retake the exam or is it at the examiners discretion.
I'm assuming that you're talking about what happens if you choose to return to the field due to deteriorating weather (not what happens if you don't return and you subsequently encounter IMC)? In which case, unless the examiner has already seen enough to be able to assess you on each of the required elements of the test, your test will be "incomplete", and you will have to fly again (no further test fee) to demonstrate those items which could not be assessed on the first flight.
(On the other hand, if you don't turn back, and you do encounter IMC, you have probably failed the en-route section of the test.)
Also, can you use the VOR in the exam to work out where you are or where you are going, heard that you could and all it means is that if you use it that you can be tested on it
For the planned navigation leg, you can not use navaids. For the unplanned navigation, you can, and should, use whatever aids are available (with certain exceptions which would make life too easy, e.g. you can not track directly to or from a navaid, nor can you use the moving map of a GPS), and will be tested on how you use them. You must, during the test, demonstrate a position fix using navaids, and also tracking to or from a navaid which will be nominated by the examiner (either a VOR or an NDB).
FFF
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