Hi all ive been having some trouble diagnosing a problem with my 2011 A3 2.0TDI.

around October last year I had a glow plug change and a day or two after my engine started making a distinct tapping / knocking sound. Took it to four separate garages and mechanics for diagnosis and all came back saying lifters / rocker arms, since then I went with a pretty reputable garage who have done the rocker arms, cam followers and they notified me my injectors had failed which I had done, went to collect the car and I can still hear the noise obviously not happy about this which I told them they said to leave it with them and they will look further into it, fast forward two weeks they are now informing me it could be bottom end. P**sed off is an understatement but I’m not mechanically savvy so I’m unsure if this could be true, have attached a video of what the car sounds like any help would be highly appreciated.