Golf MK5 1.9TDI Faulty Injector 2004

[SilverGolf19]

I have a Golf MK5 1.9TD 2004 with a faulty injector.
The VW dealer wants £1000 after VAT. He won't give me the part number.
I want the part number so I can buy a second hand injector.

Does anyone what the part number for the injector is likely to be ?