Thanks for the help guys, much appreciated there
looks like I'll be replacing the upper control arms then!
The car's done 88,000 miles. There's no squeaks, groans, nothing. The interior doesn't rattle, there's absolutely no sound at all. It sounds like a luxury saloon on the motorway. The only noise is the damn knocking at the rear left and right on bumps.
I'll buy new control arms next week
the only two things that are wrong with the car are these knocking parts, and a split CV boot. Both of which I'll fix next week and the car's spot on mechanically