Rather new at European travel. I am traveling from Los Angeles to Munich through London. On a Air New Zealand plane between LA and London, have a 2 hour layover and then onward on Lufthansa to Munich. My understanding is that both airlines use Terminal 1. Do I have to go through immigration control when I get to London? Do I need my bags with me if I do? Or is it just a simple plane change since I am in the same terminal?