Just a little update on the CPL skills test, which I assume has not changed that much recently.
The test starts with the Navigation, than diversion, after this it is either circuits or general handling, depending on what is convenient with regards to the test area.
The OP does not mention what really happen during his test, as I would assume he would, or should have done a FREDA check approx. every 15 minutes, and actually updating, cross checking the altimeters.
It is correct as last poster said, the examiner, does say that he will not talk, unless spoken to. It is possible that the examiner was waiting to see if the student would notice his error, and it possible if the flight was otherwise flawless, that he was considering to partial the student at one stage.
However at what stage would you stop the skills test based on the QNH being set wrong?
During the diversion? General handling? Circuits? During the circuits he would have been in touch with ATC, and got a QNH. What QNH did the OP write on his notepad during contact with ATC?
There are many details that the OP has not written about, to defend himself, also the OP does not explain what kind of aircraft/altimeter he used on the skills test.
Have flown Warrior, Arrow, Seneca, C172, there is no way there would be any parallax error between 1023 and 1024, seriously they not sitting in 737 or A320 cockpit! Most SEP and MEP, are pretty tight/narrow.
I recall during my skill tests, that these issues was not only checked and cross checked, but also double and trippel checked, and SPOKEN out loud for the examiner to hear what I was doing.
I also believe in the brief, the examiner tells you that you should speak out LOUD what you are doing, so that the examiner actually knows and understands what you have done.
No use of doing a FREDA check, or HASELL check inside your own mind, without telling the examiner what you are doing!
I admit I am a novice in this area, but I do agree with a majority of the posters, legal action can not be the correct way.
The CAA have an appeal process on these cases, and I can for the life of me not understand why the OP have not followed this path.
And as somebody else mentioned, probably the terms and conditions was accepted when he accepted the re-test for free. The CAA might have chosen to make a compromise and give the student the benefit of the doubt, however with legal action, he has taken it to a complete different level.
My personal experience with the CAA, is that they are reasonable if you get into a dialogue with them. Also taking action against the examiner, I honestly find distasteful in this case.
As some say, the aviation world is not that big!
I recall my CPL skills test, I did a bummer, I was asked to do the fire drill engine out, fine started all good, I had lined up perfect for the field, and suddenly recalled I had only done engine out drill, I told the examiner I had screwed up, as I had not done the part for the fire drill, examiner was happy, told me to climb up and do the whole exercise again!
However the rest of the flight had been flawless. My experience with the examiners, are that they are very reasonable, at lest the examiners I had, and my friends had, we all had some minor niggles during our tests, but they did not fail us for those things.
Not discovering his mistakes during constant checks, or maybe he forget to do the constant checks, that would have made him aware of the error, probably made it wander from pass to partial or in the end a full fail.
CAA gave you a free retest, is not an admission of guilt! (Specially if the words "without prejudice" was written in the letter from the CAA)
I once heard of a story once, where a student managed to land with the gear up, examiner passed his CPL, for this later to be revoked by the CAA and the examiner investigated, student had to do another CPL skills test!