Mounted some things last night… theoretically the battery is going to be mounted on the wall, but at 173kg it looks fine where it is. Will reconsider when the cupboard is being built.
The built-in battery breaker is 160A x 3 pole (480A), but doesn’t break the negative, so this breaker will double as isolator:
It doesn’t have terminal covers (anymore), so needs to go in a box. Quite proud of the cutout! 
EM’s now literally shipping me one breaker per day, so the old DB is still in place. Some of the old breakers are dual-mount, so might just complete the switchover this weekend even if everything isn’t here yet.