More info on my situation, my battery was getting very hot a couple of times when charging so much so that the plastic seal around the glass front and back had started to come away, I couldn't pick up calls when listening to music, I didn't have the option to create a personal hotspot dispute my carrier supplying it, I had echoes on calls and a bunch of other stuff which I relayed at the genius bar.
Got a brand new boxed retail swap out :)
The fella reckoned he knew nothing about the lack of 3G toggle. I don't think Apple are telling their staff so each person attending a genius bar session get the same "oh, you must be the only person with that problem" response...