Original game stays on Ipad turned over to another with new GC

Hi guys......i hope you can help

i have been playing Clash of clans for about a year on my Ipad2 connected to my GC account. I recently bought an Ipad air and set it up with same GC account. I transfered the game without problems, so now i can play my game on both my ipads.

Now i want to turn over the old Ipad2 to my son, who would also like to play Clash of clans. I logged out on GC and created a new apple ID. Thereafter i logged in again with the new Apple ID and GC account. So now i basically thought all was ok, and that a new game could be played.

after downloading and installing clash of clans again i started it on my Ipad2 with the new GC, but much to my suprise it opened with my old lvl 107 account....i even got a GC welcome from the new GC account.

i would like a whole new game of Clash on my Ipad2 so my boy cant interfere with my own game...can u help?