Thanks, this was the only bit of info I needed; ladder's been up for days now! It's quite sunny here this morning so your solution has come just in time to get the job done before this afternoon's forecast downpours. I do have the much easier B&Q bracket but as I almost broke next door's gutter...
I did eventually think that they might be removable, but couldn't shift them; could you explain how please? Maybe only the front clips are removable and I was trying to move the back ones? Most of these reviews report problems but nobody mentions taking clips off.
OK thanks all, but Programme_Seller had the best info. I got another from one of our 3 B&Qs; crucially, they have a single removable clip, which solves the problem of the clip lip blocking the top of the gutter length as per my pic. It's a tight fit, but you don't feel as though you're about to...
The problem is not one of friction, it's simply that the rubbers are too thick. Adding washing up liquid can only make this worse.
Why on Earth are you recommending a Stanley knife for a task eminently suited to a flat file?
But I'm not sliding the gutter through horizontally, I'm trying to force it downwards from above. The horizontal route just encounters a semi-circular ridge of rubber which won't compress enough.
I have a new jointing bracket from Wickes who say it's compatible with my Marley PVCu gutter. It has 2 rubber strips, half the thickness is recessed into a groove but the top half stands proud of the gutter valley. If I remove the rubbers it's a perfect fit, but I simply cannot compress them...