Been thinking(and it really hurt) sometimes you need a brush that is larger for doing large windows so instead of changing the brush can one be made that extensions can be put onto the side a modular brush a couple of inches either side and two bars to slide bolt join clamp to your normal brush
If this is a stupid idea ignore this post completely if its a good idea its mine i thought of it first and i have copyrighted it so keep you mucky maulers off!!!!
Dean