Have just relaced the fuel filler lock motor on my 02 plate Laguna ST and thought I'd share my experience.
The original unit started to make a loud grinding noise when locking. When I took a look at it the manual release 'ring pull' had sheared off inside the mechanism (as described else where here; thanks).
This what the old unit looks like.
Removal / Replacement
The unit is accessed via the rear light cluster panel in the boot. However, it is mounted on the bullkhead that goes into the rear wheel arch. The single mounting point is a nut on the spindle.
To remove, remove rear wheel and support. Remove the rear wheel arch liner. This is held in place by 3 screw, two nuts and two plastic pins.
Once removed the nut holding the locking motor can be removed easily.
The replacement item was £25 from Renault which I didn't think was too bad. They have redesigned it.
The thread is now metal rather than plastic and the manual lever is not a 'ring pull' any more. I hope they have changed the internal design to strengthen it.
Hope this helps,