Objective clip is knocked during top flexure attachment

When the top flexures for the objective mount are bridged over, it seems to have a tendency to knock the column slightly. It still moves OK, but it means the objective's always slightly squint. I need to either fix this, or provide adjustment.

Probably it can be fixed by providing a (snappable?) support somewhere to stop it falling over, perhaps bridging nearer the bottom of the clip.

This probably ought to be done next time the Z mechanism is tweaked, which may be a little way off. 5.17?