Suppose one has a claim against a corporate defendant, and up until the trial the defendant is represented in correspondence by a solicitor. At trial, a human director of the defendant is called by the defendant party as a witness, but the defendant itself is represented now by a barrister. If one wishes to reference claims or points made (I suppose nonetheless by the defendant, even if through its human solicitor) in pre-trial correspondence, these challenges couldn't necessarily be posed to the human director of the defendant in cross-examination, because the human director of the defendant is not actually the defendant itself, while the barrister will also not have been the one who had written the letters of correspondence (it would have been the solicitor).
If one wishes to quiz or challenge the defendant, what opportunities in trial are there to do this?
Even if we suppose momentarily that the legal representative of the defendant for the trial was the same one who had been writing all of the letters of pre-trial correspondence (ie the solicitor), as the legal representative is not a witness who can be subjective to cross-examination, are there any opportunities in a trial to enter into socratic, examination-style dialogue with the other side's representative?
And which human entity in this scenario most corresponds to the defendant itself which is not a natural person? Is it true that the correspondence despite being humanly written by the instructed solicitor was legally with the defendant, so that they may be held responsible for everything that was written therein?