Funny you should say that. I posted on another forum the following earlier this evening:
Just an update for those waiting for a Super-Lite Sill Brush. The prototypes have been in action and feedback given. We are currently at the point of having to rethink the design as we found them not to be as good as they could be. So, back to the drawing board I'm afraid. Apologies to those who were waiting for this version of Super-Lite brush.
We are working on the best possible solution but I really don't know when they will be available.