Cetus 3D MK2 not sticking to the raft

Cetus Cetus 1st Gen MK1-MK3
1

Help! My Cetus 3D MK2 won’t stick bigger prints to the raft.This print has a flat base and is about 80mm square.

I’ve tried (new) 0.2 and 0.4mm nozzles, 0.1 and 0.2 layer height, fine and normal quality settings, raising nozzle temp by 5 degrees (to 215).

Here’s the problem:

image
image635×730 136 KB

2nd smaller (about 20x50mm) print sticks OK:

The filament is this PLA: https://www.amazon.co.uk/dp/B079NLR2CY

I have had the same problem with this filament: https://www.amazon.co.uk/gp/product/B073PB9XWY

Can anyone give me any tips or theory on how to fix this?

Thanks,
Charlie.