Thank you all,
some great advice there.
I'm going to stick with orca slicer, so with that in mind i shall:
try and avoid override_config (i've moved my heater pid settings over)
not use the filamanet section on the duet and instead use the slicer filament settings
check that my slicer isn't messing about with static settings (as i do want to do pressure advance and input shaping).
@droftarts
I took the little silicon jacket of the HotEnd and i agree with you that it's a volcano-175-AS. that's really good info about the stringing as i'm currently doing teachingtechs benchmark for temperature
https://teachingtechyt.github.io/calibration.html#temp
and i can't even get one bridge working. But at least i feel a bit more confident now about why.