The part number you quoted is the black plastic insert that fits over the foglamp in a
Cupra bumper. The part number for a
Cupra foglamp (you will need to check with the dealer if this is the same as other
Ibiza models) is S6L0941703. Bad news is it was £78 including the VAT last time I got one from my local Seat dealer, and I don't think you can buy just the glass front bit. Check with Dave at Sere Motors (they have a forum in the dealers section); should be able to do it cheaper than that.