Did you install the metal spacing inserts that came with them? It helps hold them in place as well, cos the adhesive strips supplied are rubbish by themselves.
I used the clips and more double sided tape... I snapped a bit off before I 're fitted it and it was better. Gonnna have to take the window out to fix it as the adhesive I used is like cement lol and I been looking at at it and it only seems you can put them in one channel