I decided it was time for a new workbench. After some searching I chose the furniture makers workbench Premium 1, made by Ramia in Tsjechie. In the Netherlands they are sold by “Restoration company Van Zaltbommel“.
My own build process
I made pictures during my building process, you can find them in the gallery below. The steps are described in the comments.
The corner vise 
Not exactly even (straightened that out later) 
Loose parts 
Extra: pivoting wheels 
The bench vise 
Tung oil put on
Tung Oil:
I did put on the Tung oil and left it over night. There where two things that went wrong. First: I did not properly sand of the lacquer that was on the wood, second: I should have wiped the excess of after half an hour. So when I came back the next day, the bench top was a mess.
Retry, sanding down to the wood
It had a waxy coat all over and I had to sand it down to the wood this time.
Sanded down the parts 
Sanding the bench top
Assembly
Having oiled it for the second time (and wiping of appropriately) I assembled the work bench again:
Legs put together 
Drawer slides and vise jaw 
Bench vise mounted 
Preparing for mounting the wheels 
Wheel mounted 
Frame put together 
Frame attached to bench top, wheel assemblies ready to put on 
Measuring for mounting wheel assemblies 
Long screws for wheel assembly 
Wheels mounted
Putting it on its feet: disaster!
When we put the bench on its feet, the height was perfect. But when I tried to wheel it to its final position, one wheel got stuck in a hole in the floor and the whole frame fell apart…
Broken down
My suspicion it that the glue is not strong enough, the birch wood it to dense for this glue, or the Tung oil messed things up.
… after the break down 
Wheel assemblies 
This is how the glue looked after the breakdown
I will contact the supplier for advice on how to proceed; I think 45 degree cross beams are to be placed, more screws (not only dowels and glue). We’ll see where it goes from here.