While waiting for new PCBs I've been working on an updated case design. The previous case was two solid halves screwed together via 3 x m2.5 screws and heat set inserts. The two halves are still attached this way, but now there is a slide to remove friction fit battery cover. The fit needs to be tight enough on the retaining rails to not accidentally come loose, I'm thinking that a slot for a coin to use as leverage to push open the battery cover might be ideal.