All I know is last time I had a contract with them, I had a really hard time cancelling to go with O2 for the first iPhone. I spent the best part of an hour trying to cancel, with the retention guy begging and pleading for me to stay, we can do a nice deal, this nice Samsung has a touchscreen why can't you have one of those instead, can't you give your contract to another family member, etc etc etc. Every time I said "no, I want an iPhone specifically and only O2 sell those" or "no, my other family members are not interested and have their own contracts" he just repeated himself like a stuck record. Eventually I put the phone down, wrote letter that could not be interpreted in any way other than a 30 day notice of termination of contract and sent it recorded delivery.
Maybe they've had enough complaints and kickings from OFCOM that they've toned it down a bit by now though.