O2 Guaranteed 4G Upgrade?

I've been bouncing around whether to get my iPhone 5 from my existing carrier, O2, or to switch to Three, who do unlimited data.

The other attraction of Three is they have apparently reached agreement with EE to use their LTE service when it launches.

I mentioned this to a guy at the O2 retentions line today and he said O2 are going to guarantee an upgrade to a 4G handset when their service launches which "will be much sooner than most people think"

He coudln't give details but put me on the list to receive when it is announced .

Anybody else had this?

Real or bull to keep you hooked?