One of my colleagues pointed out that her Samsung phone actually shows the GPS indicator on the upper left, not the upper right. If it's truly the GPS indicator, it should be appearing and disappearing on its own, since the GPS radio is only intermittently turned on (when apps need it). If it's persisting until you clear it, then it's an app notification.
The Samsung GPS icon is a little different from the stock Android one--the inner circle is bigger on the Samsung icon.
When you say it's a "3," do you mean it's on the 3 wireless carrier in the UK? Or is it a Galaxy S3, or Note 3?