Ah thanks! I was using a very poor choice of search words.

I like the the ones suggested by freeranger and the minoura holder suggested by polyphrast which seem light and cheap, but the reviews on Amazon make me think its a hit or miss. Will have to just try one out and see!

While researching some more for a cheap solution, I stumbled upon a fork bracket called the CatEye Center Fork Bracket as an alternative central mounting option but did not go ahead with it as it is hard to reach the light from the saddle.