iPhone 6 Maps app not working or working erratically. Does anyone have a fix please?

Hey guys. My wife has an iPhone 6 which has the current up-to-date software. For the last month or so, the Maps app has been a nightmare. It fails to recognise where it is but then suddenly remembers, only to then give a totally false location.

I've done master re-sets, checked everything I can think of and still no joy.

This fault probably coincided with with a software update. If that is the case, can I take it back to before that particular update was downloaded?

Has anyone had a similar issue? Come up with a fix? Any help at all will be greatly appreciated!

Thank you.