Hi, this one is surprisingly simple...

Remove the velcroed interior in the passenger footwell (under glovebox)....looking up (awkward bending) you will see a 6mm gold coloured bolt, unscrew that and turn the motor clockwise around an inch (it can be stiff), the motor should drop from its position...simply unplug it and do the reverse with your new one. Took me less than 5 minutes.

Just a note...I took it to a renault repair centre and they quoted me 260 quid for the job. I bought a secondhand one for 35!! (new from autoparts the motor is 108)

Hope I helped