Gordon, thanks for the heads up but I suspect there is no way of beating nature. It was the regular gutter cleaning that started the process, just too old and getting older to be at the top of ladders for much longer, the tiles are circa ten years old thus it seemed that as it took circa ten years for the moss to get to this stage, if I clean it now while I can, then I suspect in ten years if I am still around I may no longer consider drainage a priority, house drainage that is..(-:
The roof rain water drainage is connected to old drain tiles underground in places, through which it heads of into the field, I have dug and cleared these in times past, not quite up to that again, I installed traps at the foot of all the downpipes and grates at the top all to reduce underground drain interventions when I built the new extensions and garage.... I just did not count on the increase in Moss growth that was never a problem when pre extensions, the old house had a slate roof..! Though I also note that there seems to be more moss than grass on the "lawn" these days too, well at least it is still green..
Don`t much care to get involved in chemical warfare...
