Swivel brushes.
Left take a 4"-6" top piece off a no2 unger. Fit a tapered dowel into the base end and then screw fit the taper into the brush. Put the swection onto the unger elbow and adjust the torgue collar to just allow it to swivel on the Elbow arm, or it can be torqued up so that it doesnt swivel. This also allows a bit of play for extending slightly over sills etc. The "secret" is that there has to be a slight or obtuse angle to make the swivel work ie it will not work on a straight pole.
Next brush right in pic.
This is the cheap way of doing it. Get a small dia. piece of dowel that will fit inside an unger elbow joint. Wrap some pvc tape around the end until it "bites" into the thread of the brush stock,fit and screw home. Measure down the dowel so that the length goes inside the elbow to the bottom and cut this length to allow the dowel to hit home inside the elbow. Again wrap enough tape round the shank until it grips inside the elbow. This will allow the brush to spin inside the elbow if you exert pressure from the base of the pole with a twisting movement of your wrist.
Next brush right is a lightened Addis with a piece of plastic manifold to accept jets.
Last 2 brushes are my own swivel ones complete with a torque collar, one of them has Peters Autobrush fitted.
Or you could buy one of Gaz's swivel brushes.
I will post this on Matts site and jouks new forum so anyone can find it.