conservatory roof cleaning is not rocket science!course you have to scrub!!

spray roof(i use virosol)
leave for 2 mins
scrub and rinse A LOT
job done
i will use customers outside taps if available as the flow is stronger and you dont waste pure in your tank.
for clear glass roofs i finish off with pure from tank.
i have 20m of microbore specifically for outside taps for add on jobs.
best wishes
dazmond