Thanks for the reply guys! Just didn't want some crazy bill to appear on my doorstep, but if the system said I was eligible for upgrade then it can't be my fault!

Yeah that's what I thought, just thought it was weird that they allowed me to upgrade 6 months early with no cancellation fee!

Hello, Yesterday I went into my local carphone warehouse as I could not remember the date I took out my current contract on my iPhone 4S which was £36 a month with t-mobile. The girl in the shop pressed a few buttons and put my number into the computer and told me I was eligible for upgrade. So I upgraded to an iPhone 5 on £27 a month and traded in my iPhone 4S to pay for the up front cost. Today I registered a t mobile online account to track my bills and it says my upgrade date is the 1st jan 2014, in 5 months time! Also my contract has not changed from £36 a month, anyone got any clue?