Be very wary of signing for Infinity UNLESS you are assured that your line will be 'improved'. As mixture says, it is all about the length of your line, regardless of where you live. A long 'ropey' pole supported line will not deliver Infinity speeds.
The EU have now 'approved' the UK's state aid application for broadband so you will need to watch the Surrey 'plan' and its roll-out. A fair bit of info on Surrey's plans on the Ewhurst and Surrey Hills website.