Just looked at those pics again & boy does that mono' look grubby, well, it's been hammered all day, still should have wiped the cobwebs off though.
I could take more plastic off the brush but that's the limit with the angle grinder, one slip & that would be the brush in the bin, i'll do the next one better. I did it for better access into sash & case windows, especialy the ones with side rail over-hangs, as the excess stock on the vikan would hit these & restrict the bristles getting into the corners. The brush just felt better allround once it was trimmed & i've used it ever since. I think it's about 10 months of solid use & has got better with age as it was a bit too stiff at first.
The tool i will do it with next time is called a spokeshave, just looked it up in screwfix, 8 quid.

Tony