Thanks for follow up Bushfiva.
Not to take any thing away from you being Helpful.
I didn't elaborate on my Unit as I am an Ex. Computer /Electronics Engineer.
So fully aware of all the aspect you covered.
The reason at this stage I havn't delved into the "Unit" is I dont want to negate my Guarantee .
I was just pointing out to others a possible Pitfall to avoid.
As a matter of interest I have upped the anti with WD Service Centre,
regading my unit and a possible repair.
I had to go into their "Small print " for them to aknowledge that the word "Repair" is even in their wordy/wordy blurb!!!!!!
I'm just seeing how far I can take this to see them squirm a bit.
Then I will take over and check step by step to isolate the Fault.