I have a paid copy of a VPN and although it operates correctly (so I can watch BBC abroad etc.) it doesn't work with maps which always zoom straight to my UK address. The VPN I use is PIA (Private Internet Access).
// I can only guess the apps are using the built in GPS?//
Maybe you'd have got more relevant answers if you'd mentioned your were using a phone or similarly GPS equipped device.
If you're on Android:
http://trendblog.net/disable-location-services-android/