Paragraph 13 Conduct of proceedings and witnesses
The parties to the arbitration shall, within thirty-five days from the appointment of the arbitrator, or within such further period as the arbitrator may permit, deliver to him a statement of their respective cases with all necessary particulars and—
(a)
no amendment or addition to the statement or particulars delivered shall be allowed after the expiry of the said thirty-five days except with the consent of the arbitrator,
(b)
a party to the arbitration shall be confined at the hearing to the matters alleged in the statement and particulars delivered by him and any amendment or addition duly made.