A4 3.0tdi engine / fuel pressure fault.

unfortunate first post but I'm hoping that someone might be able to shed some light on a fault I have with my 3.0tdi A4.

The cars an '05 with 150,000 and has started throwing up a fault at higher revs, 3500rpm and above.

The car drives perfectly in general use but recently when hitting higher revs the car will go into limp mode and the glow plug light will flash. I've read the codes and the code P0087 comes up which I believe is a fuel pressure related fault.

Does anyone know if there's any parts that commonly fail causing this issue?

I was rather hoping it a simple case of a fuel filter as I'm not sure when it was last changed but fear it may be more involved.