Part numbers (re 'stuck in Spain and DPF)

Related to my earlier questions on being stuck in Spain, I refer to a post from 3 years ago:

http://www.briskoda.net/forums/topic/173341-control-system-for-exhaust-gases/

In this it talks about a part Part Number - 03G 906 051A - which is as I understand it a 'faulty' exhaust system sensor. Firstly, do we have any concrete evidence that Skoda say this is faulty.

Moving on and the reason for asking is that the dealer replaced this for me yesterday in Spain; the invoice and the box both say 076 906 051A which the previous thread says is the replacement.  HOWEVER when I look at the actual part (which I found surprisingly easily) it is the same part number as the one they removed (which they did return to me).  The date on the new part is 2009 - and it also has a strange blue pen mark over the date.

Any more thoughts.  I am potentially going to state this to Skoda Assist who sent me to this dealer in Spain - and hope that they will see that I have been left in inappropriate hands.

Thanks for any input.