The wife upgraded her phone this week from an iPhone 5 to a 5s
New phone all okay everything transferred across but when we have gone to reset to factory settings the old phone it says needs to log out of find my phone (no longer even installed on phone)
And it’s not recognising her Apple ID password (definitely correct as it works on new phone/computer etc)
Any ideas on how to wipe the phone without a password?

Both phones where on iOS8.1

Nuclear option: http://support.apple.com/en-us/HT201263

(no longer even installed on phone)

Doesn’t matter if the iPhone is still registered with it. Have you 100% signed out of iCloud etc on the older device?

Log in at http://www.icloud.com – Find My iPhone. Pick it off the map and do Erase iPhone.

Sorted, cheers
Neither method above and not sure how but all is reset