If engine code is dw10uted4 then it's the same engine. I dug out the old receipt today.
I too think the filings in the fuel are a cause for concern. The pump drive of engine I worked on was quite tight on the camshaft, it was only a slight bluing from slipping/heating that suggested the pump drive was loose. I really hope you get a solution.
This is the Forum for all your Citroen Technical Questions, Problems or Advice.