Hi,
Just jumped onto the Vodafone coverage map for the giggles and seeing what sort of coverage I'd expect to receive if/when I move to Vodafone:
http://www.vodafone.co.nz/network/coverage/
I'm located in Avalon and in theory I should get a strong 700Mhz signal yet when I put my SIM card into my iPhone 6 I find that at best I'll get one dot for 4G but get 3-4 dots for 3G. I have a strong guess that only 1800 4G is available where I live because at least in theory, all things being constant, I should be getting a signal strength close to what I can do with 3G.