So I finally got feed up with that dam ding dong noise, removed the under dash shroud and the cluster shroud, and the cluster came right out quite easily.
The overspeed warning box is attached to the back cluster so the cluster does indeed need to be removed, you can't reach it from underneath the dash.
The noise when reversing comes from a different box altogether, witch is able to be reached from underneath. However this box also controls the automatic transmission lock, so I didn't bother with it.
Have uploaded some photos for clarity...