UPDATE

So, after some pondering, we've come to a agreement regarding what to do when the bot is flipped.
Due to the way the internal components and weapon mechanism are likely to be laid out, the body is likely to be flat-fronted with a sloping back (a la the series 5 version of Kat 3), giving us 2 options.

1. Move the drive wheels right to the back. This would be the lighter and simpler option, but it gives us no way to bring the weapon back into contention other than someone else flipping us back over, not to mention it would also make the front end very twitchy.
However, the biggest problem as far as we can see is that the bulk of the robot's weight will be at the front, especially if another robot is being dragged around in the jaws. If the wheels are at the back, there will be no weight on them and therefore very little grip.

2. Add a srimech. This would mean the extra weight of another actuator and a battery to power it, but it's a consistent and repeatable way to keep the weapon in a useful state. Also, it means we can move the drive wheels further forward, improving balance and grip.

In the end, we've decided to go with a srimech arm down the back, most likely powered by a GLA750-S to give it the speed it needs.