Conduct of proceedings and witnesses
12.—(1) In any arbitration to which this Schedule applies, the arbitrator may, in his or her absolute discretion, subject to sub-paragraph (2), join as a party to the arbitration any person having an interest in the holding, whether or not such person has applied to become a party to the arbitration, provided that such person consents to be so joined.
(2) Where an apportionment pursuant to regulation 33(5)(b)(iii) is to be carried out by arbitration, any person with an interest in the holding who has refused to sign the statement referred to in regulation 33(5)(b)(ii) shall be a party to the arbitration.