Kryptonite U-lock rattle stopper

My Kryptonite U-lock is mounted inside of my bike frame with the supplied bracket holding the lock in place. Several times the lock has made its way out of the supporting bracket and dropped on the floor - often whilst I am riding at full speed. Whilst the lock hasn't yet hit a car or taken-out another cyclist, it is only a matter of time. To try and stabilize the lock I have produced a very simple part. It clamps to my seat tube and pushes down into the Kryptonite lock. My lock no longer has an intact plastic cover where this part fixes, which made a design quite easy to produce. Newer, less damaged locks will need a different design. I know that no one else will need one of these, but since Thingiverse exists...
I have included the slvs file (Solvespace) for those who want to modify the design.

SInce I have not yet tried the part in anger, I am marking it as a work-in-progress.