Try this: http://www.petrila.net/pug/Service/index.htm
Which might help, depending on whether yours is early or late 2001, (these refer to build code 9001 on - this number is usually on a sticker on the doorpost).
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)