Add 4.727m to data values 1956-1960 to refer to RLR<br>Add 4.725m to data values 1984-2005 to refer to RLR<br>Add 4.725m to data values 2008-2016 to refer to RLR<br>Add 4.764m to data values 2016 onwards to refer to RLR<br>RLR is 10.500m below primary benchmark N1