Thanks everyone for their advice.
Took delivery today of a eGo Portable hard drive, Mac edition 320Gb for around 60 notes.
Came with firewire 400 +800 +usb cables.
Connected via firewire 400 and have had trouble finding it on my Mac.After visiting website have found it -Applications- Utility-Disk utility.
Have changed the formatting to match Intel chip (my Mac) and bing suddenly it's there

On screen prompt automatically asked me if I wanted to use for Time machine back up. Clicked yes and it's away backing up as I type.
rgds George.