I setup a Vodem for user who is now in the UK. The SIM is on a corporate plan and should have roaming enabled.  Clearly I couldn't test that here and since the user is having problems over there just wanted to ask the following.

In NZ when the vodem is inserted it bring up the software (Mobile Connect) with VFNZ as the provider and pretty much makes the connection. What should the user do over there? They are not particularly IT literate.  Will the SIM card have favoured cell providers on it and bring up the best network or does the user have to select the network from the software?