designated mapsmeans– (a) in relation to England, the 3 volumes of maps numbered 1 to 3, each such volume being marked “volume of maps of less-favoured farming areas in England” and with the number of the volume, dated 20th May 1991, signed and sealed by the Minister of Agriculture, Fisheries and Food and deposited at the offices of the Ministry of Agriculture, Fisheries and Food at Nobel House, 17 Smith Square, London SW1P 3JR;