I think right now their work queues are empty, so if you cancel the current one, you'll have no work from BBC to get.

If you're not running other projects, then you can as well keep the current model running until they "kill it", you'll get a few more thousands of credits in the meantime.

EDIT: By the way, no one actually needs to abort manually. All models will be "killed" remotely by the project server when time comes. I think it's the "trickle down" feature I've heard about but never saw in action.