i have my garden full of vegetables so I didnt want my roof cleaners applying a biocide anywhere near my crops. cant imagine the damage it would do to my beautiful little garden, instead i found a tool on google and i scraped the moss off using that tool (https://roofscraper.co.uk/) and a long pole. ill just scrape the moss off whenever it is needed rather than spraying damaging chemicals. I also didnt want them pressure washing the roof as ive heard all sorts of nightmares about people using jet washers that are way too powerful for roof cleaning and causing insane amounts of damage to the underlaying of the roof tiles.