Hi all, new to the forum (though I have stolen useful information for several years).
My Mini has always had a horrendously dirty cargo area. Granted, this is only when there is dust on the gravel roads I have to occasionally drive on, but whenever I drive in dusty conditions some of the dust wafts into the cabin via SOMEWHERE in the cargo area. For the life of me, I cannot figure out how it's getting in. Anyone else had any dealings with this?

 

There are some vents at the rear of the battery compartment that might let in the dust. Also the snubbers at the bottom of the hatch opening might be wound out too far, and the seal isn't making good contact. See if you rotate them clockwise a bit helps.