The only way around this is to mill the outside and front of my case first, then flip and mill inside with the degree of error being around 0.05-0.075mm.
This would allow me to vacuum plate the first operation on the front of the case, removing the need for super glue.

I think I could live with that...

Ideally I could get it all bang on but that is not looking like it is going to happen on this machine any time soon... :/