4. Waiver of right to object. A party who knows that-
(a) any provision of this Part from which the parties may derogate. or
(b) any requirement under the arbitration agreement. has not been- complied with and yet proceeds with the arbitration without stating his objection to such non- compliance without undue delay or, if a time limit is provided for slating that objection, within that period of time, shall be deemed to have waived his right to so object.