I usually use my karcher vac set up, with a generator. On the last few I've done I've had several badly blocked down pipes, which the vac hasn't totally cleared - so I've had to get the ladders out.
I'm doing a gutter clear today and shall be taking my pressure washer and 24' lance with some special adapted ends. One hooks over the guttering and blasts a jet both ways to each side - along the guttering. The other hooks over the guttering and blasts a jet straight down - hopefully this is the one for unblocking downpipes.
I'm going to whizz round with the vac first and get the worst of the crud out, then switch to power washer
I gave the gutters a quick survey with my mirror and pole and they are pretty blocked up. I've priced it accordingly
Dave
It's pouring with rain at the mo though!