Relevant costs shall be taken into account in determining the amount of a service charge payable for a period—
and the amount payable shall be limited accordingly.
Where the service charge is payable before the relevant costs are incurred, no greater amount than is reasonable is so payable and after the relevant costs have been incurred any necessary adjustment shall be made by repayment, reduction of subsequent charges or otherwise.
An agreement by the payer (other than an arbitration agreement within the meaning of Part I of the Arbitration Act 1996) is void in so far as it purports to provide for a determination in a particular manner or on particular evidence of any question—
Where relevant costs are incurred or to be incurred on the carrying out of works in respect of which a grant has been or is to be paid under section 523 of the Housing Act 1985 (assistance for provision of separate service pipe for water supply) or any provision of Part I of the Housing Grants, Construction and Regeneration Act 1996 (grants, &c. for renewal of private sector housing) or any corresponding earlier enactment, the amount of the grant shall be deducted from the costs and the amount of the service charge payable shall be reduced accordingly.