I am trying to calculate moving averages based on date ranges determined by
the user, i.e. the user sets the date as say 12.01.2009 and the spreadsheet
autocalculates the 1 year, 3 year, 5 year, 10 year and 20 year moving
average.

My problem is determining how to get the system to automatically set a range
based on the date selected, i.e. if user sets 12.01.2009 as the date it picks
up values in the range to average for say the last 12 months back to
12.01.2008 as an example and calculates the average over that range.

Any help welcome.