Where such market-value is not ascertainable, the amount shall be reckoned at twelve times the amount of the diminution of the annual net profits of such property.

Compensation when due and interest thereon.

1. (1) All sums of money payable for compensation awarded under section 27 shall be due three months after the claim for such compensation was made.
2. (2) Simple interest at the rate of six per cent. per annum shall be allowed on any such sum remaining unpaid after the said three months, except when the non-payment of such sum is caused by the neglect or refusal of the claimant to apply for or receive the same.