300tdi engine ticking noise

Hi Landyzoners, I'm looking for a bit of advice with an annoying ticking noise that has started on my 300tdi. As you can hear in the video, it happens when I rev the engine up, and stops/quietens down when at idle speed. I had a feel around the back of the block for a head gasket leak but couldn't feel anything. No smoke from exhaust, bubbling coolant or loss of power either. HG was replaced in 2021 with a Victor reinz mutlilayer type. Noise doesn't stop with clutch pushed down. I did notice the side/back of the block was wet with what smelt faintly like diesel, the area near the injector was also a bit wet. Could a leaking injector cause the ticking?
Just wanted your thought before I change the injector seal and test the vac and lift pump. Thanks

It's one of those "could be anything" things.

Give the thing a good degrease and see if there's further leaks. But could just as well be something at the front with a rattling bearing.

The last "odd noise" on mine turned out to be the IP itself. Who knows why. It was still working fine, but I swapped it for another that I had knocking about and the noise went.

If you think it's an injector, you could easily loosen the unions on various injectors (not at the same time) and see how that affects the sound.