MOT Failure - Opinions Please

Not quite the same but last year I had a truck fail on a tacho seal.

I had the box out to tighten a clutch pack up so after I sent if to my nearest tacho centre. They sealed it and done a record of minor work.

Two months later it failed the test as the tacho wasn’t sealed properly. They sealed it cable to sender where as it should have been sealed sender to gearbox (or something like that).

That’s the only thing it failed on but thats on my OCRS.

Can’t win sometimes.