Sorry to jump in on this, but I seem to have a similar problem.
Car seems to tick like there is a stone caught in the tread of the tyre, only ticks when moving slowly (traffic) but when I go above 10mph (maybe even less) the ticking stops, and it doesn’t tick when on idle, not that I have heard anyway.
I have a 2005 GTI and I am pretty sure it is an AXX engine code. At about 50k miles the cambelt and water pump were changed. I am guessing the cam chain and other parts mentioned above would be totally different?
It doesn’t seem to affect performance, so is it something I should get fixed or is it safe to just leave it? I can only hear the ticking noise if I have my music off and the windows down, so I can easily live with it if it is not a major problem?