hi again mate checked the diameter of the filament all seems good, ive taken the heat sink and fan off the mk8 extruder, it doesn't seem to be slipping now it just seems to be not wanting to budge at all no matter what i change the patentiometer too. although if i hand feed it through whilst extruding it through the slicer at 210C it moves the stepper motor but it still seems to struggle even when hand feeding like its resisting the force of me feeding it. could this be a knackered chip/driver for that stepper?