Gutted So not retrievable at all.

I have a USB drive permanently attached to my iMac, it updates pretty much every change that goes on in my Mac. I can even wind it back to an exactly specific date and time.

I know its doing it a lot the light on it blinks regularly.

When my HDD went on the Mac I took it in to be fixed and they said to me that recovering the data on a £160GB drive would be at least £300+the new drive+labour. Total bill would have been £500. When I pulled out the USB drive they look at that smiled at me and said, "Thank god, someone who actually backs up their info." We will fit the new drive an restore it from the drive and it will cost £200.

It saved me £300 and I tell you what I am never not doing it again.

Gutted for you mate, really am, I've lost all my info including 4 years of photos and its heart breaking.