no, I said I didn't look at the page much.
Now that I have, I've seen that their Product Comparison chart at the bottom of the page is pretty biased. Look at
this page where it clearly states that the D2 Extreme has a fan-less design and 7200rpm 8MB cache HDD. If you need 500GB then you can get the D2 Big Disk, but I think you lose out on the fan-less design (not sure about that).
I wasn't trying to say that the G-Drive was crap and the D2 was better, but simply that a D2 may be a better storage solution than a non-existent G-Drive. In other words, if you can't find the G-Drive in the UK you might want to look at the D2...maybe.
Edit: you can usually upgrade an external by putting in a larger HDD, assuming you can open up the enclosure, although I'm not sure about the larger drives. I've only done this with small drives (<80GB) so I'm not sure if the larger enclosures may be limited in their capacity by the chipset or some other hardware. It's best to check with the manufacturer.