Dressage levels

[CentrestageSHS]

Hiya, I just wondered if somebody could give me a quick rundown into what is expected at each level in dressage. I know at prelim it is basically walk, trot, canter. Novice you start doing a few medium trot strides, and counter canter. I know the level of engagement etc. must be better for a working trot at prelim than a working trot at medium lets say but I just want to know what extra stuff the horse needs to be able to do at elementary, medium and advanced medium.
I know its a thick question but we are having an arguement at work and do not have the tests to hand to prove I am right!!!

Thanks guys

 

[Tempi]

Prelim - walk/trot/canter/medium walk/free walk/20m circles trot and canter/ cantering across diagonal

Novice - walk/trot/medium trot/canter/counter canter/medium canter/rein back/free walk/medium walk/15m circles in trot and canter/ 1/2 10m circles/change of leg through trot over x/walk to canter (only in a couple of tests)/ give and retake reins in canter and trot

Elementary - all above plus collected walk, trot and canter/10m circles in trot and canter/leg yielding/ 1/2 walk pirouettes/simple changes

Medium - all above plus travers/shoulder in/ half pass in trot and canter.