PendragonUK,
I would recommend a clean install. You may find Sproggy's forthcoming (as in VERY near) Phoenix Mini to be very well suited for your netbook, since it uses many more native Xfce applications.
You COULD install task-xfce, but then you won't get all the tweaks that Joble and Sproggy have employed, plus you'll still have the heavier Qt4 and KDE libraries present (and experience the same performance hit when you launch apps that use them).
parnote