Dynamic. But I think it has been showing this for some time. Then again, I don't reconnect very often. My last reconnection is currently showing at eight days. I think the Newport Pagnell business started before that, but I'm not absolutely sure.
It doesn't really matter, except for a few weather sites etc, which appear to assume I want the forecast for NP. I also notice that if I search for a high street store, for example, Google will produce me a nice map, showing branches close to NP. As a rule, I'm not searching for a local branch anyway, but rather their website, so it doesn't really matter. It just feels a bit strange, after a while, when it's the default supposition for everything.
I've got nothing against Newport Pagnell - although I think I only know it as a service station, which is hardly flattering. For some reason, I just seem to notice it more than the assumption always being Sheffield.