It is hereby agreed that, subject to such differences as may from time to time exist between the methods of administration in Great Britain and in Northern Ireland of the services covered by this Agreement, the Government of Northern Ireland undertakes to keep the scale and standard of comprehensive health services in Northern Ireland in general conformity with the scale and standard of such services in Great Britain, and to ensure that the rates of remuneration of persons employed in such services in Northern Ireland correspond as nearly as may be with the rates for such services obtaining in Great Britain.