i do a few regular conny roofs for existing customer every few months.if they are no access issues(like fence in the way so you need ladders)i charge anything from £15-£20.these are small roofs though and take around 20-30 mins to clean.
if its an initial clean thats filthy and i need ladders to access the roof panels nearest the wall of the house.upwards of £60.at the end of the day we all charge what we see fit for each particular job depending on access,size and how dirty it is.
i have quite a few annual cleans of roofs.usually £30 is acceptable for my customers if i can just reach with my pole without ladders with no tfr needed.good add ons in spring/summer.
regards
dazmond