The Lord Chancellor, in making regulations under this section as to the amounts payable to counsel or solicitors undertaking any description of legal aid work under this Part of this Act, shall have regard, among the matters which are relevant, to— the time and skill which it requires; the general level of fee income arising from it; the general level of expenses of barristers and solicitors which is attributable to it; the number and general level of competence of barristers and solicitors undertaking it; the effect of the regulations on the handling of the work; and the cost to public funds of any provision made by the regulations.