I don't have the mitre fence in question, but the standard cure-all for this problem is a centre punch and an 'ammer. Apply liberal quantities of centre punch dimples to the sides of the mitre fence bar; this gives the effect of widening same where the metal mushrooms out from the dimple. Obvious when you see it, but not so easy to describe. Hope that might help your situation.
I have one of these tables & one of the 1st things I noticed was the loose fitting of the mitre slide in its slot.
I have therefore never used it.
When I looked in the instruction booklet I saw the view of an upgraded version.
This included a bar for finger jointing.
I rang woolfcraft & was told they are illegal to use in UK so that model isnt availible.
I made a bar to fit & tried it out.
That's the last time.
No wonder it's illegal.
The workpiece is very unstable when cutting & can fly anywhere.
Good thing I wear a face mask.