Hi Brian,
Thanks for the suggestion.
I checked that I had the latest firmware according to the unit ie 1.54 but then went on the web to find that there is 1.60.
Applied that - made no difference.
Then took the advice of another poster.
I used gparted-live to make a bootable CD and then created a partition with Ext3 (GPT). Took a couple of hours.
Put it back on the Linkstation and it found it immediately.
Not the best use of an afternoon having to swerve round some crappy software.
Cheers again,
Adam