Minor progress as I’ve been on a run of night shifts.
Something is a bit odd with that flipsky dual 4.2 aside from the usual problems. One side will not run bldc in sensored mode. Detects OK but the motor instantly cogs up when you try and run it and hits abs max. Other side is fine. I’ve swapped the motors around and it seems to be one side of the controller causing it. Been careful to not have can active when doing the motor config and have done so on both sides.
The biggest odd thing is it will run foc sensored OK so I guess that’s what I’ll go with.
Longer mounts arrive from @dickyho 
so I can make a bit more progress. Think I’m going to wait for my diebms before I do a final put together though.