Add 5.930m to data values 1954-1962 to refer to RLR<br>Add 6.272m to data values for 1963 to refer to RLR<br>Add 5.930m to data values for 1964 to refer to RLR<br>Add 6.272m to data values 1965-1979 to refer to RLR<br>Add 5.930m to data values 1981 onwards to refer to RLR<br>RLR is 11.100m below primary benchmark SHN 30169 Aliscafos