Looking underneath at the 2 supports, the one closest to the broken wood (bolt), there is no gap, the slide frame seems to sit on it.
This is the end where the sofa scrapes the floor.
If I look at the other end(red pointer)there is a gap between this one and the slide frame..it also seems to be on a slight angle.
Do you think I if I undid the bolts on the one with the gap and bought the frame down to meet the support it might fix the issue? I guess that would 'pull' the frame up where the bolt is loose...
Any ideas?

Here is what it looks like from the front of the sofa (slide) kick plate:
Left (Broken) side

Right side:
