Morgan Freeman and Liam Neeson give directions.

You have to watch the video below right to the very end, especially if you're a film buff like me. It's one of the funniest things I've seen for ages! Thanks to author, Karen Wyld, for pointing me in the right direction. I have a lot of trouble with sat navs myself - although this doesn't involve Morgan Freeman talking to me, only me talking to myself. Sad, I know.