[Phil G4SPZ]

As you say, earthing is still of interest, but now that the majority of electrical socket outlets are protected by RCDs, earthing a chassis fed via an RCD is no longer strictly necessary as a safety feature. Others may disagree! However, if your electrical installation contains MCBs or fuses - as mine did until recently - all exposed metalwork should be earthed.

Personally, I prefer to retain the original core arrangement when replacing a mains lead.