Get a plastic plunger oil can with as small a tip on the end as possible. Fill with a mix of 85-15 of Waxoyl and white spirit. Spray the oil down around the plastic trim surrounding the rear wiper spindle until it slowly oozes out onto the paint. Repeat until the cavity is as full as you can get it.
On the estate ,open the two access panels on the rear aft of the wheel arches. Pull back the sound deadening and spray the mix at the top of each arch to panel join allowing the excess to slowly run down the cavity between the two .
Re the door tops , insert a narrow plastic wedge between door and rubber seal and lift enough to get the tip of the oil can in ( hence the reason for getting as small a tip as possible ). Slowly run the wedge followed by the gun slowly spraying waxoyl as you go until there is a good film between the two surfaces. It will be slightly rippled but will flatten out again in a couple of days as the mix creeps.I do this several times a year , it takes less than five minutes to do both areas and so far has prevented any rust appearing on my facelift.
All the areas I've seen Omegas rust can be prevented by simply cleaning the salt and grit off and simple maintenance.
I'm about to re waxoyl the inside of the door and tailgate bottoms .This time of year is best when the warm weather assists the mix to creep into all thos e immpossible to get to cavities.
"Clean it and keep it "

Don