Did this get resolved? I have the same issue. Just upgraded to 4G 30 day rolling SIM only tariff and having problems setting phone to 4G. Been on phone for ages to VM without success, except confirming the SIMs are 4G and seem to work in an iPhone (no actual 4G signal in our house but LTE setting saved).
We have 2 Z10s and 1 Leap. All having same issue. Select anything with "4G" in it in the Network Mode in settings and it simply revers to the "non-4G" equiv. So, 3G&4G becomes 3G; 2G&3G&4G becomes 2G&3G etc.
My only guess is that one needs to be actually receiving a 4G signal to save the setting but that would be odd.
You mention seeing 'LTE' on an iPhone that the SIM cards were inserted into. If that displayed and achieved a data connection then your 4G connection was operating correctly at the time.
Some iPhones may require a carrier settings update (I have seen this happen on a colleagues handset) that will then display 4G instead of LTE, but there should be no difference in coverage or connection speed.
I am curious to know if you have had similar issues with other network's SIM cards that are 4G capable?
The problem is with the Blackberry, not the iPhone. That was only used to test the SIM. I am hoping that it is a signal issue and that when I am in a 4G area the option can be chosen on the BB - but that seems odd. Why would one need to be in a 4G reception area to set the phone to receive 4G when the SIM is supposedly enabled?