Complex sentence: The second stage of the re-development--the building of the corporate and media facilities--commenced on 6 September 2010 was completed on time in summer 2011 and the corporate facilities are now open to the public.
Split into simpler sentences: The second stage of the re-development--the building of the corporate and media facilities--commenced on 6 September 2010 and was completed on time in summer 2011. The corporate facilities are now open to the public.