Engine Knocking

[Mark h]

Is there any gurus who might have come across this knocking noise, I was pulling away from a set of lights normally and it sort of lurched forward a bit and then started knocking louder than What it is now. I poodled it back home, about 700 metres. Thought the belt had slipped but turned out it hadn’t. My mate did a new belt kit and dephaser but it was still knocking, so just replaced the lifters and it’s still knocking. Quieter than what it was though, sounds like it’s coming from the top of the engine in between 1 and 2, thanks in advance