Here you go Mike:
http://www.amazon.co.uk/s/ref=nb_sb_...eye+lens&ajr=0 
It's worth bearing in mind that it's not a proper lens - it's a fisheye adapter that seems to sit over the top of the normal lens. As such, it's not as good optically as a dedicated lens would be, but I think it's your only option. Should be fine to have a play around with though.