don't you use the special chemical to remove the lichen ?
I also have made up tools that remove lichen in a few minutes - you need more than just TFR and water fed pole brush
Darran
Yes I use Swafega anti mould anti mildew, 5L bottle. I diluted it in water, it is great for grime and green mould, you can hear it fizzing on application and then it is easy to WFP brush it off and then rinse.
It does struggle with Lichen though. Even when I was able to stand on a flat roof and get good downward pressure it took ages and ages to scrub 90% of the Lichen off, I still did not get it all off.
You have got me thinking though, about making up a scraper on a pole or like another poster mentioned bronze wool pads attached to a pole.