LOROL services are class 9 too, no idea why. Maybe Boris has aspirations to run to Paris Nord.
We have some class 3 ECS workings, which are known as express empties, for the reason already stated above, that they are running empty to form a passenger service further down the line and can't be held or the passenger service they are to form will run late. We had a job which had a class 2 terminating at Selhurst, which became a class 3 to run empty through Selhurst yard, which became a class 5 at the signal to exit the yard and a class 2 again on arrival at Norwood Jct to run in passenger service again. All within the space of about 5 minutes.