Daz, you're doing the right thing; just miss those odd windows. Really, you shouldn't have walked on conservatory roofs anyway!
Sometimes, by using different angles with the pole, you can get at really awkward windows, or by using a longer pole (I use DIY Fishing poles) you can reach these awkward windows, but if you can't get to them, just leave them.
The worst that will happen is that you lose that account; and that has never happened to me over an odd window that I couldn't get to.