Sorry to hear about your experience and after spending 400 dhs, noise is still there.
I was thinking about your problem, this morning while getting my Pajero oil change at Mobil and thought your problem must have solved and that's why we didn't hear from you back - as that's what 90% people do - hit and run
@hAwX how did your lifter noise got sorted, please share your experience.
Reading again, this raises a bit of suspicion that previous owner might know this is coming soon.
Anyways, Habtoor being a dealer should have answers to all Mitsubishi queries but unfortunately, my experience with them was very robotic and they specialize in scheduled service like machines doing their job. Little left or right leave their boyz scratching their head. It took me 3 visit and 4 specialized technicians at Habtoor with some internal wasta to get refer to sound technician and still in end left with an advise "Sir your car is old, please buy new Pajero".
Problem: Minor knocking, pinking and missing resulting in doof doof noise like a tractor.
Later on @Barry diagnosed of a bent exhaust valve changed it and fixed the car in 2-3 days times. Now he is no longer working as a mechanic, but still, help people in diagnosing out of goodwill.