Google Maps - My Location

Sitting in a Kwik Fit outlet in Barry, South Wales whilst getting 2 new tyres put on my car, I was fiddling around with Google Maps to pass the time.

I clicked on the "My Location" feature which I'd used successfully before. Today however it insists that I'm in Hamilton, New Zealand. Cleared and reset GM and got the same result. Odd. I'm sure I'm in Barry, UK!