It looks like its more common than I thought and not just a geometry flaw of a small Defy. Will just have to be more mindful of it at junctions so I don't end up on my arse.
It's a trend in bike design really, more compact frames with a shorter wheelbase, especially on racier bikes. It'll be worse obviously if you have mudguards fitted, have big feet/shoes or have replaced your original cranks with longer ones.
Also bear in mind that while the Giant Defy is available in 5 different frame sizes, there are only 3 different crank lengths fitted to those frames so there is a bit of a compromise/crossover in sizing there.
I wouldn't worry about it too much, it's only a problem at very low speeds when you forget about it. When you are riding at any speed above a few mph you don't actually turn the wheel very much at all. If you turn the wheel that much at higher speeds you will be having a crash anyway regardless of whether your toes touch the wheel.
Much more important to get your cleats in the correct position otherwise you can injure yourself through improper riding position. When you are riding you should feel like the power is going through the ball of your foot, not your toes or heel.
I have a bit of mudguard/toe overlap on one of my bikes and I can still trackstand on it if I am careful.