After much frustration and expense, I have determined that the problem was not related to the DVD power, but to the SATA connection.
When I tried probing the drive plugged into either the Primary or Secondary SATA connector on my HP Pavilion motherboard (Asus Amberine with ATI xPress200 Chipset (RS480)), all I was getting was PhatKey failed.
So I bought an X360USB Pro to allow me to connect the SATA connector to the USB port, and hey presto! It worked!!!!
The strange thing is the drive was recognised by JungleFlasher, but it just couldn't seem to read the flash. Not sure why.
ps - Thanks Ako, you're right the OP/CL issue was nothing to do with it.