§ 11." That where income arising during the lifetime of the settlor is by virtue or in consequence of a settlement made on or after the tenth day of April, nineteen hundred and forty-six, payable to or applicable for the benefit of any person other than the settlor, it shall, unless it is income from property of which the settlor has divested himself absolutely by the settlement, be treated for surtax purposes as income of the settlor; but this shall not apply to any income if the income is payable to an individual for his own use or is applicable for the benefit of an individual named in the settlement, and the individual to whom it is payable or for whose benefit it is applicable is neither in the service of the settlor nor accustomed to act as the settlor's solicitor or agent."