Originally Posted by El Presidente
Not sure of specifics on removing, but you'd most likely need to go the custom ROM route?
You'll be able to tell if it's 3 firmware via the boot animation, if you see a 3 logo displayed during boot, it'll be 3 software. Also look out for pre installed 3 apps (like the Three app for example).
Alas, yes to the boot animation. (I don't mind ignoring the apps and the boot - but will it mean it wont get software updates when I change my sim card to O2?)