By notice in writing served on the Registrar and on all parties to the proceedings, a reference under section 31 or 32 or an application under section 33 may be withdrawn at any time before it has been finally disposed of, but such withdrawal shall be without prejudice to the Tribunal's power to make an order concerning the payment of costs incurred up to the time of service of the notice: Provided that the Tribunal may proceed with a reference on the application of the licensing, body named therein, notwithstanding the purported withdrawal of the reference by any other party thereto.