ive done it, it was about 5 years ago, i was asked to clean the gutters out on a 3 storey OAP home
here is what i had
a UNGER 3 X 3M ali pole
a bracket ( they sell them in B&Q and focus ) they are used to hang things on in the garage, they come with a red plasitc end cap, do a search on the B&Q site for 0000003599211, i drilled a extra hole on the pole and bolted it on, its as solid as you can get
a pressure washer drain rod kit attachment, mine was 15 M long, which was great, its a pipe with a presure tip on the end that you can feed down blocked drains, i zip tied mine to the pole and the bracket to form a angle, zip tie it about 1 inch from the end, the bracket slides along the gutter and the washers blasts out the dirt
it worked well and the price was nice, the pressure washer drain kit was 30 quid, the bracket was 3 quid with a few quid for some bolts