Alzibiff

Still struggling! I can import two models and the brim works as it should on each but when I merge models, the brim disappears. This has happened on both multi-model jobs that I have sliced in Cura 5.4 so it isn't anything to do with a specific file. This is very infruriating as the latest print - merging two models -  I want a brim in order to avoid warping on a 14+ hour print. Quite happy to accept my shortcomings when it comes to CURA settings as this is a new bit of software for me, I just want to know whether there are any settings I can try?
 
EDIT: I have just resliced but told CURA to use Extruder 1 as the build plate adhesion extruder rather than leaving it at the default which seemed to work fine with other jobs I have prepared so I sort of have a solution now! (Odd that if I selected Extruder 2 as the build plate adhesion extruder, I still didn't get a brim. Hey ho!).