I don’t recall the number, it's probably buried in an old trip report somewhere, but we had 2 hours solid riding on Swarm once. This was a photoshoot for the park organised through Thorpe Park Mania to photograph the ride with riders on for press release when backwards Swarm was that years thing. I'd guess about 30 circuits?
It was freezing cold and soaking wet, still great fun though. I know I felt rough the next day, just like a big hangover.