Complex sentence: These two departments were merged as the Granada Yorkshire Factual Department based at ITV Yorkshire in Leeds after ITV Plc was formed, This then becoming the Northern Factual Department of ITV Productions before being closed down.
Split into simpler sentences: These two departments were merged as the Granada Yorkshire Factual Department which was based at ITV Yorkshire in Leeds when ITV Plc was formed. It later became the Northern Factual Department of ITV Productions before being closed down.