Beerdrinker, For any 3G Ipad to use an external GPS you have to be in airplane mode (very appropriate I guess). You then have to turn ON Bluetooth and check that the GLO/Dual/Elf is connected.
I am not sure if the Glo has an App to show the Sat status. Both the Dual and the Elf do.
Re Nexus ... CapnBloggs ..how do you ensure you are using the Ext GPS?