Add 6.304m to data values 1923-1964 to refer to RLR<br>Add 5.999m to data values 1995-2016 to refer to RLR<br>Add 6.029m to data values 2016-2020 to refer to RLR<br>Add 5.922m to data values 2020 onwards to refer to RLR<br>RLR is 10.400m below primary benchmark UD 40