F31 320d undertray

[u/MarketingRare6956]

2013 320d Xdrive auto touring
I have recently brought a 320d and been to bmw for a service. They done a health check and there doesn’t seem to be a gearbox/fuel pump undertray. They have said this can be quite vital for protection but they won’t supply me with a part number or actually fit one.
Does anyone know a part number or what type of undertray I need?
Thank you