What exactly do you teach as Ex 3?
Any syllabus that is written down is quite vague on this, because it will vary so much from school to school, instructor to instructor and student to student. However, since it is a lesson, and in most cases it will be the student's first ever lesson (if not their first ever time in a light aircraft), surely it must start with the very basics. That, to me, would be attitude flying, and using the controls to alter the attitude.
Of course there will typically be a large element of sight-seeing in the lesson for commercial reasons. We want to show the students how much fun it is to fly a light aircraft, and if the first lesson is all work and no play then the chances are they won't want to come back for more. But there must be at least a degree of instruction.
On this basis, I would say that it is not possible to give the lesson at night. Without a horizon, it is not feasable for the student to be receiving any kind of meaningful instruction. This flight would be treading the very thin line between Ex 3 and a passenger-carrying flight requiring an AOC (which, incidentally, would not be possible even if your company had an AOC to the best of my knowledge, since night flight must nearly always be IFR in the UK and JAR-OPS doesn't allow single-engine IFR).
That's my opinion. I believe you are correct in that there is nothing written down anywhere which says explicitly whether or not night trial lessons are allowed, but by thinking logically through the question you can form your own opinion and either agree with me or not.
FFF
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