O2

The end of my contract is on the 30th of October.I'm currently going to switch to a sim only 30 day contract (temporary) on the 30th of september, and leave o2 on the 30th of october. Do I have to give the 30 day notice on the same day i switch to si...

It's a few months till my contract finishes, so starting to look at deals and so on. I'd like to switch to Sim only contract but not sure if I have to wait till my contract ends or be able to sort one out currently?