Well it seems some companies do listen, I just received this email from them-
Hi Joel,
This product was designed according to Specifications, to fit the Jumbuck Kettle BBQ, that is sold in Bunnings. As you are aware all Kettle BBQs are slightly different dimensions.
Due to the interest in this product, Smash should be developing a model to fit the Webber Kettle in the near future, please keep an eye on our Website for updates to this information,
Thanks you for your support of Smash Products,
Regards,