Do you mean part call? I’m sure your elite legal skills can unearth the answers for you...

Also, as to differentiated trainee pay in the same firm - that sucks if true. Not few years ago RLT and PTC trainees were all paid the same. Personally, just suck it up and prove your worth. It will be a painful (though barely in the grand scheme of things) but at least short six months. But have a think about the financial health of an organization that has to scrimp a couple of hundee sticks from its trainees... be good if you can name and shame.