You’re right that it appears upside down, but I’ve found other pictures of cadets with this rank, and it’s in the same orientation. I haven’t been able to find an explanation for it.
It’s the Regimental Command Sergeant Major insignia. Now where that figures into the whole cadet rank system, I’m not exactly sure; there are apparently cadet officers and cadet NCOs, but I haven’t the slightest clue how that actually works.
As a WAG, having that many chevrons plus that many rockers plus the internal star and leaves, placing the chevrons upward would placed the rockers below the elbow, obscuring them if the arm was bent. Reversing the direction meant that only the tips of a couple of chevrons would be hidden.