I've learnt how to get people to move out of my way, especially when I'm on my biddenbike: I call out, 'moogie, moogie!' and jiggle my bike up and down a bit. If the person doesn't move, then I ride into her back. He he, I did that to Mum - THEN she moved! She learnt what 'moogie' meant pretty quickly after that. It's the closest I can get to 'excuse me' at the moment.
But I do try to be polite. When Mum gives me a biccie or a drink I often say, 'anks, Mum'.