Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X2 from the PCB

Measurement:

Test 1:
Test the resistance between the Blue (2) of the disconnected X2 connector and a suitable Earth.
Expected resistance 1 MOhm or greater.
Test 2:
Test the resistance between the Brown (5) of the disconnected X2 connector and a suitable Earth.
Expected resistance 1 MOhm or greater.
Test 3:
Test the resistance between the Brown (5) and Blue (2) of the disconnected X2.
Resistance should be approximately 3.2 MOhms.