Mate. Ive had a similar and worser experience.
I took my driving test 2 months ago. My examiner was a woman. In the test, I drove quite neatly. I never hit over 30 mph (mostly 25-30 or slower when necessary). I always checked my blank spot, observations and mirrors before signalling. I only turned at junctions when it was clear.
On quiet roads, I drove quite slow (around 10-15 mph) and gave way to people oncoming when necessary.
After the exam, she failed me for 1 serious mistake of steering at a junction. I turned very slightly left because I didnt want to hit the kerb on my right. I was kind of like "What?!
Ok then..".
However, the problem was that she gave me a hefty 16 minor faults. Including 3 speeding faults and alot of other unneccesary faults. Which means that she would have failed me anyway because I wasnt allowed to do the second manoeuvre because of my serious mistake.
I remember driving normally and she would just be ticking the paper unnneccesarily sometimes.
I think she did this because she was a racist and I am a 22 year old muslim male and she just wanted to ruin my life and make me wait another 3 months. Maybe she was having a bad day too which is not our fault, is it? Very heartless people out there. Never keep your guard down.
Signalling is quite important mate. Instructors are very strict. One small mistake and your f**ked basically.