10It shall be the duty of each Electricity Board, before 16th October preceding the beginning of any rate period in respect of which that Board will fall to be treated as occupying, in a rating area, a hereditament of a rateable value calculated in accordance with Part I of this Schedule, to transmit to the Commissioners a statement setting out particulars of all matters estimated, calculated and certified (otherwise than by the Minister or the Commissioners) for the purpose of computing the rateable value of that hereditament.