When they were talking in the café, neither Sarah Jane nor the Doctor made any reference to their meeting in "The Five Doctors" & both spoke as if they had no memory of it. No explanation has been given for this apparent amnesia, nor has it explicitly been confirmed in-universe that they didn't remember those events. However, "Time Crash" and "The Day of the Doctor" both indicate that participants in multi-Doctor encounters often don't remember the events due to shifting time lines. This may impact companions too. And "Journey's End" confirmed the Doctor's ability to erase memories.