In the early 90's as a young lad with 2 yrs engineering experience behind me, company I worked for went bust
I went for this test with the MEB identical type of test except the wiring was t&e surface switch to batten holder clipped on a wooden board
At the time there was a a lot of competition due to the recession approx 2500 going for 4 posts!
There were people there with HND's trying to get a craft apprenticeship !
I got rejected due to the wiring test
It was perfect !
Clips and components spaced to the exact measurements, but my downfall was that I hadn't done it in the exact same order the instructor had ,
he smoothed out the T&E made a bend first and fixed the components to board and installed cable then did the switch first ,
I'd done wiring like this before and just cracked on and did it very slightly differently batten first thinking a bit of speed would make me stand out as it showed I was competent
At the time I was annoyed as it was better than some of the others who did get through and the Instructor even told me so
The point was a lot of their safety procedures are set in stone for obvious reasons and by doing things in a slightly different order can be very dangerous especially with the equipment/ voltages they work with.
So my advice would be listen and watch carefully and follow to the letter