Old Clash of Clans account transfered - how to create a new village?

I have worked with Supercell to transfer my kid's CofC village from my GameCenter account to his. (He had started playing on my machine under my account but he now has his own account.) That is now resolved.

However, since he used to play on my machine, his village is still the one that loads when I launch the CofC app. It's not attached to my GameCenter account, but it's still the one that appears by default. Obviously, I don't want to play my kid's village (and in fact I can't even launch the app when he's playing on his side). How can I start a new village and link it to my GameCenter?

I'm thinking that a possible course of action would be to (1) backup, (2) restore to factory settings, (3) login to GameCenter and create a new village, (4) restore from backup. This should work but it's a bit involved. Anything easier?