I regularly get mine "dirty", nearly once every Sunday it ventures off road, lately the conditions have been pretty mean.
There's more Sussex in the footwells than in Sussex!
I do a lot of off road motorcycle events and pull a bike trailer over some pretty filthy farm tracks, fields, farmyards, woods and boggy meadows without any trouble.
The last event I went to saw an XC90, New Rangie and a Defender (Defender was shod in some mean Cooper STT's) bog down and need a tractor to pull them clear, while I did a lap waving goodbye to everyone!
The car is so light, it's not digging in and sinking, ripping up the ground. Once or twice after it's been left parked up all day it's sank enough to require a bit of gentle throttle and a rock to climb out, but otherwise it's hardly bruised the surface and managed to grip pretty much anything needed.
I've found it's limits and it's not been grip, but rather approach angle.
The front bumper/splitter underneath is far too low, so much so I'm considering cutting the splitter lip off.