After writing previous reply I went on youtube and found this video which answered my question
Anyone whos interested here
https://www.youtube.com/watch?v=rxGvg_ZHsMI
The end caps on those brushes have been replaced with a softer plastic to prevent them making such a loud noise when hitting the window frames which solved that problem.
Them brushes have a lot of nozzles on the rinse bars so the set up needs larger pole hose (8mm) and ideally 8-10mm hose on the hosereel to get a really good flow of water to the brush to be really effective without using too much water.
If using 5 or 6mm pole hose then it's too small, which is reducing the flow of water too much to make it an effective brush which in turn flattens a battery as the flow rate has to be turned up too high to compensate for a poor water flow..
They are quality brushes but ideally the bristles could do with being longer for first cleans but are sufficient for regular cleans.
I could never go back to a regular stock brush (except for ancient art deco style very curved glass style windows) as I would get so impatient waiting for a decent coverage of water to start cleaning the windows, anything else just feels so slow in comparison to using these brushes now. Using a regular brush with a 5mm pole hose is like waiting for Xmas, takes forever.
