APPLE...
The problem of a missing AirPlay icon and missing AirPlay devices has not yet been fully resolved. The variations I've seen (on an iPad 4) are
1) There is NO AirPlay icon, only AirDrop
2) The AirPlay icon is there but when you open its popup the local device (iPad) displays at the top of the list followed by one other device. If you now wait the shown device scrolls sideways and shows another available device
3) The AirPlay icon is displayed and its popup window contains a current list of all available streaming devices. This is what we want!
HInt: Possibly there is something going on concerning the streaming capabilities of the available AirPlay devices. I've noted that my AppleTV is usually first up when devices start to appear and this offers picture and sound streaming (also screen cloning from suitable devices). After this the audio only streaming devices appear.
APPLE PLEASE RESPOND TO THIS !