There are official ways of filing complaints about the conduct of a test (but not the result). However, as you say, this probably isn't appropriate in this case if the student has already gone on to take his Attempt 2 and passed.
My suggestion would be to have an informal chat with the CAA Chief Examiner (Helicoptors). Make sure that you have a list of specific things which were said which you feel were incorrect or unjustified, rather than just generalities, and definitely don't make it personal. It might also help if you have examples from more than one test, since all of us have off days (whether we like to admit it or not) and the examiner might have just been having one of those days. And if you have other instructors who will give similar examples from other tests with other candidates, that might help too.
Once you've presented the evidence, the Chief Examiner will, I would imagine, decide whether he should have a quiet word with the examiner concerned.
Anyone got any other suggestions?
FFF
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