Your advice probably saved me from a lot of hassle Roger, so thank you from me..!
I'd tightened my nut after it dropped off, but clearly the sort of tightness that would ensure it would never come off again unless a three foot breaker bar was attached. Having read your post & looked at the photo's, I slackened them off so there was play between the bracket and the rail.
I just happened to mention this whilst at the breakfast club at Allon Whites & I got the sort of look that can never be mistaken in any language..clearly one must NEVER tighten this nut too tight..!
So thank you.
