Ross do you do that from bottom or top?
Thinking of getting a gutter vac this year.
Just don't fancy going up ladders
If the bottom of the downpipe has access, then it's from the bottom but if the downpipe is blocked by a plant growing in the top of it where it joins the gutter, usually the answer is, and sorry to say as I know you've had a fall, to get up a ladder and pull the thing out.
If there is no access from the bottom of the down pipe, whether you use a jet wash or just a hose, I can't really see any answer other than to use a ladder to access the top. Sorry.
I don't honestly know if a gutter vax is much use for unblocking down pipes or not. Maybe others on here can help with that.