For £600 you could get a Giant Defy 3 or 4 road bike???
Sent from my GT-I9100
But the OP's asking about hybrids...
My two cents' worth, which will probably be soundly mocked, is that if you can see yourself getting a decent road bike in the nearish future, then don't get too "road-y" a hybrid now, as in terms of general performance there won't be enough difference between the two bikes to make it worth having both. On the other hand, if you got yourself something of a trail-natured bike, then you would be able to find out that you like the cycling, and then when (not if, lol) you get your nice road bike you'll have one great bike for smooth n speedy stuff, and the other for pootling and knocking about the local bridleways.
One thing oft-forgot about "trail" hybrids id that you can always add slimmer and smoother tyres which is a very cheap way to upgrade your bike's topographical range. Whereas if you buy a fast "road" hybrid (ie in this case, the Giant Rapid), you may find that if you want to beef up the tyres and take it on a trail, you might struggle if the frame is closely-built around the wheels.
In my case my Cannondale hybrid is (for me) perfectly placed between the two styles and has clearance for a good width trail tyre (40mm or 1.6") as well as being able to carry 28mm slick road tyres if I so choose. It's probably more at home on the road. But I digress...
If your local shop is a Giant dealer then you are spoilt for choice, and they should be able to order in any stock they haven't got. With all the above in mind, and chauvinistically assuming you're male, I would have a good look at
http://www.shopgiant-bicycles.co.uk/217/products/2012-giant-roam-1.aspx which says RRP of £580 but you might find it cheaper. Or the Roam 2 which RRPs at £500.
I'm quite surprised at myself for recommending this genre of bike actually! But it seems to fit the bill here.
Stu