Welcome Stephen:
I have no experience with the EN standards. That being said, traceability may be limited to the base metal only or it can be extended from cradle to grave.
Some of my projects use a weld map to keep trace of the materials used, joint type, WPS, filler metal, dates of, who fitted the joint, who tack welded the joint, who welded the joint, class of weld and acceptance class, the test method, the NDE procedure, who inspected it, whether it was accepted or not, and if necessary; the repairs and reinspection.
Some small projects only need evidence the correct material was ordered, no CMTRs required. The job might require the welder to apply an identifying stamp adjacent to the weld.
The extent of the documentation is either as per the QC/QA manual or as agreed to by the contractor and the Owner.
I have personally inspected and recorded the test results for over 10,000 fillet welds on one project. of those welds inspected nearly 90% needed to be repaired.
I don't know that my response is of any solace, but it gave me a chance to say hello.
Al