I have had some difficulty completing the collision model on time due to my unfamiliarality with the tools I am using, but this is a valuable learning exercise with regards to making estimations in future.
I have made progress implementing Pocket collision and Ball to Ball collision, which each behave differently to each other and to Rail collisions, and have created issues on GitHub to reflect this.
Detection in both of these incidences uses simple Pythagoras to determine the distance between objects and checks that they are not within range of one another using their radii, but for this to behave as expected I have introduced new mid-point properties for the objects in question, which I initially overlooked. I also account for the ability for balls to overlap over the edges of the pockets, provided their centre of mass is not intersecting with the pocket.
Once these steps have been completed I should be able to create a testing scenario to visualise that this aspect of the model, which should then be complete.