iPhone 5 EE UK 3G plan - Can't turn off 3G

Hi all,

I have an iPhone 5 on EE here in the UK. I'm on a normal 3G plan (no 4G) but I wish to turn off 3G to save battery life when I'm out, I normally turn it on when I need to browse etc however I only have the option to turn off LTE on my iPhone (even though I don't have a 4G plan)

By turning off LTE I am still left with a 3G signal.

I'm guessing this is a carrier issue. If I unlock my iPhone and put say an o2 simcard in there will I get the option to turn off 3G and then out my EE simcard back in?

Regards,

SSD