I was on park yesterday. Stealth has been closed since last week and is not going to be back up any time soon due to new parts required.
Apparently Thorpe have recently fired the AM engineer for Swarm, as such they can not operate it until the PM engineer is on site at 16:00 (whom lives far away).
Make of it what you will, but sure enough Swarm opened bang on 16:00, with only one car and an immediate 2 hour queue line.
Source: ride operators on park