I personally wouldn't pay £600 for leathers but then thats because I am too tight!! :lol
In that price range you'll be comparing against AlpineStars, Arlen Ness, Dianese, Spyke etc. etc... personally I would go to your nearest Heing Gericke and look at their one piece suits which in my opinion look just as good and are built to last.
I have £379 Hein Gericke two piece leathers, bought in 2003 and going strong despite little care (one zip pull did snap but I fixed this with a paper clip!)