Hi Casey,
Thanks for your reply. That is what is happening – in fact I don't even need to "start" looking for a cache, the blue bar appears when the app is launched, and does not go away until I manually close it in the app switcher view. This happens regardless of whether I am looking for a cache or not.
The location setting is set to "Only while using" which is what I think you're referring to. I'm not really happy to let the app use my location "always" (which is the other option. Setting it to this makes the blue bar go away, but again I'd rather it wasn't using my GPS constantly ).
It was working fine until a few days ago, so maybe a recent update has changed this? If it's any help I'm using an iPhone 6 Plus with the latest version of iOS.
Cheers,
Mark