Hi Dave is this your setup?
http://www.guttercleaningsystems.co.uk/karcherkit.html
If so how do you rate it? did you have to buy extra tubing/ guessing yes?
Especially on blocked downpipes etc; have you been beaten by a clogged gutter?
Do you have a generator or do you plug into custys electric?
Can you work in the rain using this equipment?
Yep weather here essex/waltham abbey crap 
many thanks lee
Yes Lee, although they've recently added two extra heads

so it's better now
I've only been beaten by one plant that was deeply rooted - although it was bracken fern and had been there at least 9 years - It was in my own guttering!
I've had a couple of jobs where a slate or tile had dropped into the gutter and some where at the high end there is limited space between slate & guttering, nothing a blast with a jet of water and a recheck with the mirror hasn't fixed
I use customers electricity, even at commercial jobs - never had a problem with them questioning it, and I don't use it in the rain, a couple of times it's starting spitting with rain - but I've always finished before heavy rain started.
I can't comment on any other systems - but I would recommend the karcher kit - it's a trade rated vac and it does what it say's it'll do.
I treat gutter clearing as an add on extra to window cleaning - wouldn't want to do it all day, every day, but as long as I'm earning the same as I can when window cleaning I'm happy to do a few guter cleans
Dave