Mk3 1.6 tdi engine rattle

Hi. I've got a pronounced rattle at tick over, goes on increasing revs, also goes if I'm rolling slowly forward and apply brakes.

Belt etc changed 40k ago.

Is it possible to get access to the belts and then run the engine to try and figure out what's rattling?

Also i believe injectors can cause knocks, can this be checked somehow?

Thanks

Mick