(1997 'P'-reg Xantia 1.8i LX hatchback)
In each case I have highlighted the part I'm interested in with a white outline. It's a metal D-shaped hoop.
Suspension set to lowest position:

...and the highest position:

The reason I'm asking about it is that the loop is open and appears to stretch and 'slay' apart when the height-selection lever is moved to the upper position.
I'm wondering if I'm looking at something which is about to break!