Tonight I finally got my panniers back from Overland Solutions. To get the fitted bike back took a bit longer than expected, but I guess that's part of the "handmade built to order" thing. (There was actually a very long queue with the local powder-coaters they use).
Ernie from Overland Solutions really did a fantastic job, and everthing fits snuggly. It's a bit heavy and the bike's very different to ride now – but it really is a bullet proof pannier system, which I know is waterproof, safe and won't cause any headaches on the way.
(BTW: Thanks Ernie for helping locate the 'clonking' kind of noise that came from the drive chain!)