If it's anything like the front then it's held in with plastic clips which are easiest to cut out with side cutters. Not simple to remove without destroying them. At about 20p a clip to replace, not worth the effort of preserving them.
Thanks for the reply. I would like to know what panels to remove to gain access or are the plastic panels simply a push on fit that is easy to ease off like a door trim. I do not want to damage the panel trying to leaver it off only to find that some parts are screwed and end up denting the otherwise perfect paint and panel, and also adding to the damage of the plastic skirt which is corrently only showing minor damage, but would be better repaired off the vehicle.
Should be just clipped on , a bit like an interior door trim. Use a slim lever and prise it off. Once you get the first clip off it should be easy enough from there. As Crispin says, get replacement clips fist and replace them all. Also, seeing the clips helps in the removal as you can see how they 'work' and where best to lever.
IIRC, the front ones slot into the plastic flare from the bottom. i.e. pulling the trim up will unclip them the trip, leaving the clips in the body work.
You cannot put it back on in reverse though, the clips have to go into the trim and then pressed into the body.
When I was putting in the snorkel a firm tug on the plastic trim caused it to unclip from the clips. This does damage the clips though and without new ones, it will not sit flush against the body.
All the above is with the front fender and an old memory. Rear ones and a youthful memory may disagree
@Crispin Do you have any idea where I can buy the clips off the shelf? Some foul member of the underclass bashed my car while I was parked, which meant I had to remove the near side rear plastic panel to stop it flapping off completely. I need the news clips so I can refit it.