It is possible yes however the eas console light still works .
since all ive done is electrical than surely its a fault .
Or a dodgy wire in the ecu plug .
There are a couple of ways of disabling the EAS and EAS messages, one is a dedicated cable and one is by bridging two pins in the ECU. Don't know which two pins though. If it's properly disabled can't see how disconnecting the battery could effect it.