is your spare wheel loose perhaps?
heatshield loose?
Cheacked that aswell and its fine?
exhaust hanging too low and knocking on the rear axle?
as above, sounds more like leaking shocks/bushes
fitted spacers recently? wheels loose
has your car been lowered?
Have you fully removed your rear shock from the car and tried pumping them?
Mine had been knocking badly on the drivers side, I've just removed both rear shockers and the drivers side one is shot. No resistance and leaking.
Take it to a renault specialist maybe and let them test drive it. Hutchies near barnard castle.