Hi There, you nailed it, confliction with Stansted departures. Leaving the hold at FL80, the aircraft have to head south west then be at or below 5000ft before they can be turn downwind for runway 25. The bases of CAS don’t allow for an early descent option, and Stansted airport didn’t want to change any of their departure routes, this there is a confliction.
The Stansted Luton traffic interaction has always been challenging, the new Luton hold has just moved the confliction points and changed the way the issues need to be resolved.