So...forget the pouch-bag. I ruined it. I'll come back to it later as I haven't given up on it yet. It's not that complex either, but I guess it just wasn't pouch-bag-time and I probably was too sloppy with it from the start.
So, the alternative is this small childrens bag. Same colours, made with the beach in mind.
...and now it's going to find its way to small Yorio in Paris.