Configuring both devices to tether to my TP link router. When tethered the app reports connected using WEP security setting for both!
 

I see the last firmware update enabled the default setting to WPA2-AES, however this isn't working on my configuration. It is not a selectable option during tether and I don't see anywhere to change it.

How can I enable or change the WiFi security setting to WPA2-AES either during the tether setup or retrospectively?

Suggesting I restart a clean tether process for a fourth time is not a practical solution, on this occasion.