hi GB i got my 5L pressure sprayer from B&Q (£15)its handy for roof cleaning and fascias.
tfr is from a local car parts supplier.
i use either the vikan rectangle mono or the stiff vikan sill brush depending on how dirty the job is.the vikan sill is great for really stubborn muck.
i use the vikans for these jobs as they have better scrubbing power than the supalites IMO.
by the way ive never had an issue with scratching plastic with the sill brush but i wouldnt use it on a self cleaning glass roof as it might affect the coating they use that supposedly make it "self cleaning".

regards
dazmond