Tommo you're a champion, invaluable all of that! I've seen most of what you mentioned in the little trawling I've done but wasn't sure what it was like for everyone else. Right now, probably a 'refresh' of the dampers, top mounts etc you mentioned sounds like a good idea, any rough ideas how much they go for through dealerships?
The knocking sound occurs for 5-7mins after I've switched the car off completely. Surely the exhaust shielding wouldn't be rattling for that long?!
Next stop getting in touch with the Renotech / AP Automotive!!
ps. Any common Clio II faults to keep an eye for? steering wheel is looking quite at the very least