Help Help with odd location problem

[wooky69]

For the last few days my phones weather app and a couple of other apps think I'm in another town that I went to last week. If I open Google maps though it shows me in the correct location. It's set to use course location rather than GPS.

I did upgrade my Desire S from Gingerbread to Ice Cream Sandwich a few days ago but it did initially show the correct location.

Can anyone suggest where the problem may lie?

Cheers.