“The end caps did not fit the roof bars, and so had to be cut down 2-3mm on both sides and across the bottom, as well as making the recess for the bars deeper by a similar amount. The locks then fitted and turned easily. Removing them was a nightmare, they jammed and I had to lever the end caps off. In the process 2 of the locks sheared. I then cut the end caps down further and I can now lock and unlock the remaining 2 locks. So the locks themselves are OK, they just don't work with the supplied end caps without modifying the latter.”
Sorry to hear you have had some issues. The covers can be tight, but will still fit when located correctly. We sell many of these and although tight on the first fit, they will be easier once on and by being tight will not rattle or vibrate on the car.