Yes, normal PLA, 0.4 nozzle, loaded as a project. I'll have a go at importing models and unchecking adhesion (the greyed out area had been a problem!). I re-installed Cura prior to printing and removed all previous configuration files to avoid anything we'd done (we have screwed up settings on other jobs in the past).
Thanks too, dorlik.
I've used the AA nozzle but we may have made some other similar oversight or indeed a screw may be loose - I'm reluctant to start fiddling with that unless a last resort but I think slowing it down for now at least is a good start.
This thing's evolving rapidly and I see Amazon wading in with new open source designs and supply now. However, if demand for face shields continues then I may look at purchasing a larger nozzle to speed up production.
We're using our company's machine and also have some obstacles to overcome with challenge from our legal department about whether we can use our company machine for this 😞