Well folks, it was a beautiful but brief friendship. The Roll Out gutter from Rainguard worked - but with a few problems -
- It did roll out as advertised (see picture) but it does have difficulty across obstacles and non-downhill slopes - so that where snow, or the edge of a path etc gets in the way, the roll fills up with water, and made me somewhat nervous about whether this might cause a back up at the top of the downspout eventually.
- It sprang a leak. It was very minor, appeared in one of the creases of the tube, but this then caused a reduction in pressure so that the tube did not fully roll out.
- Aesthetics - I've got to say, it just didn't look nice! Even if I had used a white elastic band, there's just no way that a platic roll looks good nestling at the bottom end of your downspout!
By the way - why not just extend the downspout away from the house? Well, it feeds to a landscaped area, and beyond this is a path. I would dig a trench but I don't really want to have to dig under the path or remove the stones to do that - yet...