What description did it give other than "O/S/R Sensor fucked"... Cohernace issues or target not recognised? You will need to look at the wheel again i'm afraid and you may also need the machine or an oscillescope to hand.
Firstly, get the vehicle jacked up on that corner and wheel off.
Secondly, inspect the sensor wiring, general condition of the sensor itself and most importantly the "reluctor ring" paying close attention when looking for signs of cracks (You will need to rotate the road wheel to inspecting the full rolling radius).
If the reluctor ring target is cracked it will need replacing which on the Clio II means replacement of the rear disc assembly as the rings can no longer be purchased on there own and they're shrink fit items also making htem tricky to fit for the average DIYer without gas bottles. Then, if all is well with the rings connect the diags or oscillescope and look at the sensor in questions live data output. Does the sensor detect rotation when the wheel is turned? If so, how does the graph or indicated wheel speed look? It should be progressive and smooth with no sudden jumps in value. If you see no movement disconnect the sensor and inspect the multiplug pins... if they're correded up to hell clean then with a small wire brush and loads of contact cleaner, replace and re-try the function test. If all is well with the pin condition replace the sensor.
Mick
