The Employment Tribunal seems to be mainly there to make sure that the employer had jumped through all the (very complex) employment laws hoops and dotted all the i's & crossed all the t's before giving the unwanted employee the heave ho.
Especially that the correct number of verbal and written warnings etc etc had been issued and in the correct format.
The tribunal doesn't much worry about the extent of rule breaking. If the employer could prove a rule had been broken after all the preliminary warning processes had been complied with, that's the end of the story.
Hence Mr Masson's decision not to use a legal representative to check the i dotting and t crossing was very mistaken. Even big companies HR departments usually screw up the detail sufficiently for a lawyer to make a case.
p.s. I'm an engineer, not a lawyer!