You are not charged switching. There is still so much misinformation about the switch and the BT system to switch you is not fully working depending on what package you have ie there is a problem with some accounts switching if on Halo3 package.
I tried to switch earlier this year it wasn't possible due to an issue on my account which only got fixed last week after 7 months. So I decided to stick with BT for now as it was cheaper to go Full Fibre but had issues with that too. See the thread full fibre nightmares.
I also have been told if you switch to EE and you have voice calls you lose your phone number as you cant transfer it. You get a new number.
Some people have switched fine, some have switched and wanted to switch back. It's like a minefield in a Lucky dip sand box.
