2005 A4 2.0tdi- oil /water leak from rear of engine?

Hi All. My 2005 BLB engine has recently started to drip oil onto the drive. I removed both undertrays to see a fairly wet oily scene with the oil coming it would seem from the rear of the engine up near the cylinder head area on the offside. There is also some pink coolant drips amongst the oil.
I cannot see any water on the dipstick, nor oil in the coolant expansion tank so I am hoping its not the cyl head gasket. Old oil around rocker box seal is semi dry so I think this leak is south of rockerbox....
It is tight and crowded around the rear of the engine up against the bulkhead so impossible to see much at all.

I believe there is a coolant flange made of plastic at the rear of the cylinder head, and maybe this is leaking and the oil is seperate??

Anyone had this issue? Any ideas what I should be checking? Thanks in anticipation! Bob C.

There is a plastic flange on the back of the head which would be my first job. We have a customer with the exact same car and have been fighting an oil leak which we suspected was the tandem pump or cam cover but after replacing the gaskets for both and brake cleaner and pressure washing the back of the engine, we can see it is from the gasket and in theory that is the end. We have given him an estimate for a new head and he is mulling it over but it would not be a sensible thing to do although he has spent considerable money with us keeping the rest of the car in tip top condition mechanically.