Welcome to the forum and your soon to be new purchase.
The majority of the issues you will come across on your new Eriba will be down to the cabinetwork. Eriba have cut costs by using lightweight board that does not hold screws well and also cheap hinges. The screws will work loose, top cupboard doors will move and your bathroom door will probably decide to open en route and could well part company with the bathroom wall. But do not worry as all these things are preventable.
1 - Remove a couple of screws in the top locker hinges to determine the actual length and what you can go up to. Buy the next suitable length up. The problem you will have is the head size on the Eriba screws seem to be small for the gauge of screw. Replace all of the screws one at a time, adding a blob of pva glue on the thread. As pva is a water based glue this will make the wood fibres swell slightly and you will get a more solid fix. You do not need to use an epoxy resin adhesive such as Araldite.
2 - Add some form of simple turn-button or bolt to the top of the bathroom cabinetwork. I made this up for my Eriba.
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3 - The issue with the door is due to the bathroom cabinetwork flexing, resulting in the door popping open as it un-latches. If you look at the top wall cupboard over the seat opposite the entrance to the van you will see a small gap between it and the bathroom wall. Ideally you should fit a packing piece in this gap and screw through bathroom wall into the top cupboard side.
4 - While you are at it, if you are ocd like myself then you may want to replace the crews that hold the window fittings in place. They are poorly plated and will tarnish and eventually start to rust. 25 or 30 x 4 csk are from memory the correct side.

That should have most things covered, but:-
I would keep an eye on any fittings that are stressed, such as the bed mechanism.
Some owners have reported problems with the Knott coupling.
Touch lights a few years ago had issues with flashing but this appears to have been fixed.
Hide a door key somewhere in a plastic bag taped to the chassis. The door can self lock if it closes with any force.
Reports of water ingress are starting to become more common. This could be due to increased sales, I don't know. You need to have the official Eriba Water Ingress test done by the supplying dealer each year. Sometimes you need to book this up a year in advance.

Colin