Reference method

[Nemises]

Hi guys I'm new to the forum so go easy .
i passed my testing a while back but have only been testing houses, I'm now testing a commercial building and for all the power and lighting twin and earth is used which is contained in basket along the corridors then masonry zip tie holders as the circuits go through other rooms then clipped down the wall to the boxes.
what reference method would I record C or E.
Thanks

 

[davesparks]

Both as it is installed with both methods. Or else work out which is the most onerous and record that