(a) prescribing the class of dispositions or operations which shall be deemed to be transfers to controlled companies within the meaning of section 17;

(b) prescribing the matters to be treated as benefits accruing to the deceased from any such controlled company, the manner in which their amount is to be determined, and the time at which they are to be treated as accruing;

(c) prescribing the manner in which the net income and the value of the assets of any such company are to be determined;

(d) prescribing the manner in which the accounting year of any such company is to be reckoned;

(e) prescribing the manner in which the shares and debentures of any such company passing upon the death of the deceased are to be valued for estate duty;

(f) providing an upper limit by reference to the value of the property transferred by the deceased to any such company and preventing duplication of charge where duty would otherwise be payable in respect of both the assets of any such company (or a proportion of them) and the deceased' s holding of shares and debentures in any such company;

(g) prescribing the conditions upon which and the extent to which transactions in the name of any such company shall be deemed to be bona fide transactions for full consideration; and

(h) generally for the purpose of checking the avoidance of estate duty through the machinery of any such company.