A thin smear of grease on the two ends of the shackle really helps too, specially for when you have it forced round something and they're slightly out of alignment.
Just ordered my third one, the other two have been no trouble and the mounting brackets actually work. I would suggest some graphite powder in all locks to keep them lubed.
Gotta keep it lubed.
There are other OnGuard discounts on the Evans website BTW.
Ridiculously heavy though. Would recommend kryptonite instead.