Am I correct in thinking that you are wanting to cancel the data add on for the Apple Watch and then just be connected only to the iPhone via bluetooth?
If this correct, then the only thing you will lose will be the ability to connect to the mobile network from directly on the Apple Watch (for example, with the data add on, you can leave your iPhone at home and connect to the EE mobile network directly on the watch to do things like take calls, texts and to stream music).
