in the meantime I’ve managed to print all these fine:
6 x Schist Walls A-Wall-Schist
3 x Schist Walls A-Window-Schist
1 x Schist Walls A-SchistDoor
1 x Schist Walls A-SchistDoor-Beam
1 x Schist Walls A-Door-SchistDoor-v0.1
I’m thinking it’s definitely down to the infill.
Printing again with 20% infill it failed at one of the hollow points again got the attached imaged.
The top section seemed to float above the rest – this is a section with just the outer wall and infill.
I snapped the bit above the second set of openLock holes to see inside (although it was already splitting slightly in one corner).
I’m upping the infil line width to 0.6 and bumping up the temperature to 215 to see if that makes an improvement.