This isn't something that I've had to deal with so I could be way off base, but isn't there a SQL query defined as part of the set up to access the ODBC data source? Could it be that you need to update that query to refer to the new field?
Hi Phil, Thanks for the response. That approach didn't work. So I thought I would give the sync button (found at the top of the File > Manage > Database dialogue box) a go. I thought this was just for syncing field content and wouldn't solve the problem but it did. It discovered all new fields from the data source and brought them across. So problem solved.