Slash, you've moved me from the middle of the Saharan desert to the middle of the southern Atlantic ocean! Seems the E-W position is right, but on the other axis it should be about 53N on the northern hemisphere (full co-ords from Wikipedia: 53°28′0″N 2°14′0″W - pretty sure that's what I entered at the start!)
Y'know, not sure how feaible this would be, but perhaps a nice way of placing oneself on the map would be to have an image you can directly click on - would stop all these Brits swimming off the coast of France for instance
A higher resolution map could also be nice for densely packed areas, but obviously would be harder to navigate overall.