Time Traveller Trilogy (Mackay)

I'm not mad, ok? I know this sounds off the wall, but I was just walking to the corner shop and this girl almost got hit by a car. She grabbed hold of me and told me her name's Agatha Black and she's here from the past. At first I thought she was nuts but maybe it's true. She doesn't get traffic, she's freaked out by photos and she's terrified of TV. And she knows about the past-body snatchers, making fires, and pet monkeys. Her dad does a bit of time travel. But obviously, he's not very good at it. I mean, he got her lost. Now it's me that has to get her back ? to 1812!