No not necessarily. The Revenue could choose to withdraw the proceedings. Or if they need some time to satisfy themselves that your partner was not trading, they could adjourn the matter on the original return date, then withdraw the proceedings.
If this is a misunderstanding the court would not thank the Revenue for unnecessarily taking up court time, and the Revenue won't want to do it. They may take some convincing if three years of warning letters were not responded to before now, but keep working with them, be very proactive in giving them information, and they may be happy to just withdraw the matter.