I was in a cottage in Gloucestershire this afternoon. There was a small multi fuel stove in the lounge that had not been used for quite a while. It was connected to a 6 inch flexi flue liner, but there was no provision for sweeping it. I had to pull the stove out and to my surprise I found the whole stove pipe was blocked with twigs, and when I swept the liner yet more twigs came down. A good reason to get a cowl with a bird mesh fitted.