I would have extended the ladders to rest on the gutters , and cleaned the windows ! Am I missing something ?
I tried to work like that in the beginning. It often meant that the window was out of reach - especially near the bottom. Then I would put one foot out onto the tiles to allow me to reach but that didn't feel so safe. I ended up walking up the tiles but that can be dodgy when they are wet and/or mossy. Those sort of windows definitely better by WFP IMO.
Spot on Shiner, they are so easy now I'm wfp, I used to have to lay the ladder onto the tiles and get the boss to foot the ladder, that was the safest way to do this type of window, I did them on my own a couple of times and I had to walk on the roof holding onto the window ledge, Crazy or what but we all did/do it.