Scottish...run to the hills - these are the worst type in my experience, the 'hedgehog' style is much more effective, the grids a ' mare to fit (under the lip of each gutter clip, round corners) and remove - you need to move the ladder every .5-1m or so (hedgehogs you can use you WFP to 'push' them into gutter. The grids are flat, so offer an ideal 'ledge' for debris to land on and accumulate as well as decay and fall thru the grids.(more than the hogs) I hate working with this style all in all avoid if you can and go for the hogs... that all said my area is literally a Forest so we get a lot of debris, maybe in towns they may be ok (but doubt it ?)