Re: Static vs dynamic IP?
ISPs are quite likely to allocate you a dynamic IP address from a block that reflects your region, for quite sensible routing regions. You can often see this sort of thing simply by looking at reverse DNS names for the IP address currently assigned to you. Here's an example, allocated to a person who indeed lives in Derby, routed via Leicester (as a traceroute proved):
An address being allocated to Cornwall in the morning and the Outer Hebrides in the afternoon is rather less likely.
Furthermore, some dynamic IP allocations are 'sticky' in that they can conceivably remain associated with your net connection for an extended period of time, even if they haven't been statically assigned to you.
Geolocation isn't what makes IP addresses personally identifying, however. It is just one piece of a much larger profile that google can build up about you. Knowing you are connecting via Zen from an IP listed as being located in Bracknell using IE7 on Windows XP means is going to leave you in a pool of perhaps a few hundred or a few thousand people. Once you start searching for baby clothes and donkey porn like you did last week, google will know and could conceivably carry on tracking you even in the absense of the usual google cookie.
That aside, given a time and an IP address, it is quite possible to find out where the connection was made from. Your ISP will have address allocation logs, for example. This can be tracked back to your phone line, your SIM number or a MAC address of a WLAN card, so unless you actively take steps to conceal yourself, you can be found.