Regulations may provide for the making and recovery in such manner as may be prescribed of such charges as F1the Secretary of State may determine in respect of the provision of such services under this Act as may be prescribed for such persons not ordinarily resident in Great Britain as may be prescribed; and the regulations may provide that the charges are only to be made in such cases as may be determined in accordance with the regulations. F2 The Secretary of State may calculate charges under this section on any basis that he considers to be the appropriate commercial basis.