Configuring APN through EMDK - Not showing on all sims

I have successfully created an APN and set it as default using the EMDK. This is on a SIM supplied through 3. Using MCC code 234 and MNC code 20.

However doing the exact same thing ( apart from MNC=08 ) on another Sim suppiled by BT OnePhone. The APN doesn't show in the APN settings.I know that the APN exists because trying to create it again with the replace option off will error saying that it already exists.

Tests with MNC and MCC on the 3 SIM, show that if they do not match the ones on the SIM then the APN is filtered from the list. Which makes complete sense.

My concern is that there are other fields that we cannot set that might be causing an issue.

For example, we need to set Authentication type to PAP but there appears to be no option in the EMDK profile for this.

Any help would be appreciated...