W124 weird suspension issue

[Timmychim]

Hey all, wondering if anyone can throw some light on a weird issue I'm having with a W124 230CE.

Its a knock like you'd get from a worn bush/arb link etc from the OSF, but its intermittent (sometimes won't be there for days) and when present the speedo needle wobbles (rock solid when not present)

Any help diagnosing would be gladly received!