^ i agree with jonathan/feline... on a £300 odd guitar, getting pickups that are even "decent" (and imo certain duncans are better than "decent", just BKP are "superb") is a plus. EDIT: also, having the duncans will probably mean you have more time to think about what you want to upgrade to (as they aren't so bad that you'll want to rip them out straight away, like some stock pickups), which is never a bad thing. I guess a final advantage is that when you contact tim, he'll know what the duncans sound like and so can give advice as to how to improve on that...
however, if you can find one, i'd be inclined to look for a washburn wi65pro, if you can still find one, that is (edit: they're discontinued, but not that long ago, they're basically the current wi66 pro, but without the fancy maple top). Not too long ago, they were going new for around £300, same pickups, but mahogany body and set neck, versus basswood and bolt-on neck on the wi200 (nothing wrong with basswood or bolt-on technology, just for that style of guitar i think mahogany and set-neck is better/more traditional)... and they were made in korea instead of indonesia for the wi200, which normally signifies slightly better construction quality...
would be worth a look, at least, i'd have thought.