If you have to clean whole roof..... (assume u do as obviously will stick out like sore thumb again
) i would pass on job .... without sheeting / full scafolding... whatever fsc u use cutting in , would need turbo with traces of as10! thats face it the gym doesnt give a sh*t how u clean it pedestrians council no chance - well I am talking around here ... jump on us straight away esp as they are aware of it - how would u cover that risk / method - not exactly discreet location.
Coating ...easy cut in ridge by hand rest airless controlled pressure - looks like a raised gable + side sheeting protection via scafolding.
I thought you could hire Acs ?? maybe good option
Bdcs how can you be worried about small amounts of pigeon guano for hs, yet use paint stripper 3 stores up ?
ladder - Cat extending versions + extensions not tied together
Or pass it to a roofer replce tiles prob cheaper
Good luck!