Swarm and Saw are unfortunately the only best themed rides at Thorpe.
While I agree that Swarm and Saw are the best themed at the park I always feel the theme of Nemesis Inferno is often overlooked. Don't get me wrong it isn't as good as the two mentioned above however. The mountain, you walk up into a volcano before you start flying around the rain forest-esk world.
For a ride made in 2003 I think it is quite good (again I am not comparing it to any American counterparts here)
Although back on topic, the new billboard this season is a very good addition, it is a shame it isn't more British themed to match the rest of the area however when I went last week all the effects were working and it was very nice sight indeed.