Is that Sussex Weal, Harrow Weal or Weal Eriba in Corn'all

So…. Purchased a damp meter - no evidence of damp in the washroom. Removed the washroom window - again no damp (but a little rust on the staples holding the rubber trim). I next removed the aluminium waist trim. As you can see from the photos the problem immediately became apparent. Water had managed to get past the mastic and underneath the aluminium skin. As far as I can see there’s no evidence of any rot. Fresh mastic ordered, old mastic to be cleaned off and van left to dry out before putting everything back together.

Any tips regarding reassembly would be helpful, i.e. should I try to get some Waxoil in there or would it inhibit the mastic?

20180416_142031.jpg - Bild entfernt (keine Rechte)20180416_151301.jpg - Bild entfernt (keine Rechte)20180416_155258.jpg - Bild entfernt (keine Rechte)