This may help someone with a similar problem.
The bumper on the front right side had a bulge where the previous owner had pranged something and dislodged the front corner of the bumper. No amount of external persuasion could get it back in so I found the following solution.
I removed the front right wheel. To the front of the wheel arch there is a section of the wheel arch protection that is held in place by three hex nuts at the top and two underneath. Remove these and remove the panel.
On the outer part of the wheel arch where the external panels begin there is one screw (can't remember what those Renault star shaped screws are called?) Remove this.
If you now look up and right into the area to the front of the wheel arch you will see another hex screw. This screw is a key type screw. It will not come off. It purpose is to lock the panelling to the body of the car.
Open the bonnet. Above the wheel arch in the panelling you will see the top of this screw and also the two groves cut into the panelling to which the screw must be rotated to release the panel.
Holding the socket in one hand and watching the position from above you can release this section of the bumper. The bumper will not come away fully but just enough to see the next fixing point. In my case the source of my problem.
The next fixing point is a grove cut into the plastic bumper this grove slides onto a pin. Both a easily visible. The grove and pin had separated. Levering the plastic back over the pin the plastic returned to its original position.
To replace everything I followed the above instructions in reverse.
Note: When the wheel arch protection is removed there is a piece of electric trunking attached to the back of it. I believe that this is for the fog lights. There is a connecter just inside the engine compartment behind the wheel. Mine came apart directly when I removed the panel however you may need to reach in and release this. When replacing this it can be a little difficult as you cannot see what you are doing and have to rely upon touch to make the connection.
Hope this is helpful to somebody.