Hello Johan
I hope that you have not painted the markings on yet.
Your original WD is CX5712917
I do not have the unit it was attached too.
The WD number was across the back and the front of the trailer. It has been seen along the bottom, middle and top left on the rear in both as original stencil and filled in.
With the larger springs your trailer was converted to 10CWT.
It is unusual that the data plate was re-stamped.
Hope this helps.
Eric