Hi Meg,
I am an ancestor of the Kerrs, just not sure quite how we are related. My grandmother Jean (Jane) Kerr was the daughter of John Kerr who worked as foreman at Etna brickworks. Have you seen the photo of the Kerr family of Armadale on Flickr? I believe the young lad in front is John Kerr but can't confirm this. Hope I'm not too late.
Cheers
Clair