Sorry I maybe didn’t explain it very well. There are earths at sockets & switches through the twin CPC’s yes. What had been noted was that now that the new boxes weren’t attached to the conduit like the old now defunct boxes were there was cable passing through unearthed conduit.
Then there's no code.
If it were singles through the conduit, there is an argument that it's equivalent to class I so needs to be earthed/bonded (as exposed conductive part), but pvc/pvc is double insulated, so it's equivalent to class II and earth/bonding isn't required.