It was a couple weeks ago that the Chaos Dreadclaw was removed from the Forgeworld site, and finally there is an answer now on what is going on. It is discontinued, and so are three other models. These are no longer available, however some of them will be re-designed. Here is a response from Forgeworld.
Forgeworld- 4 kits discontinued, some may be redesigned
I noticed that the Ork Fighta, Original Lightning, Aquila Lander and Dreadclaw Drop Pod were removed from the forgeworld website, and decided to ask them about it on facebook- I got this reply
Anything that is removed from the website is, sadly, discontinued. Some of these kits (such as the Lightning) will be redesigned in future, but the Ork Fighta will not be, largely because of the new plastic kit available from Games Workshop