BTW, was it you who had some query with the rear fog- and reversing lights some time ago and asked me for the fitting instructions?
Yes, it was me.
I was trying to understand how to access those screws.
Ciao Ale
Those screws are accessed from the inside of the car and not from the underside. I remember jacking the car up and checking from underneath, and also removing the trim panel from the inside; but can't exactly recall how I approached it. Well, after mulling over what I did for the past few days, it all then came back to me!

Good luck