Tom McKee K4ZAD
I'm going to show my stupidity about radio station call signs in your part of the world, but my curiosity has got the best of me.
Here in the US the FCC closely follows the table of international call sign prefixes in assigning call signs. However, you list stations 2CA, 2CC and 7ZR as fairly close to your, so they are not in GB/Northern Ireland or Saudi Arabia as the call sign table requires.
I know that Australian marine and amateur call signs are per the table. Why so different for the AM band?