[Cyclops]

Originally Posted by chaley

See the tweak gui_pubdate_display_format. Tweaks are found in preferences -> advanced -> tweaks tab. You need to restart calibre after changing a tweak.

Documentation from the tweaks file:

# Format to be used for publication date and the timestamp (date).
#  A string controlling how the publication date is displayed in the GUI
#  d    the day as number without a leading zero (1 to 31)
#  dd    the day as number with a leading zero (01 to 31)
#  ddd    the abbreviated localized day name (e.g. 'Mon' to 'Sun').
#  dddd    the long localized day name (e.g. 'Monday' to 'Qt::Sunday').
#  M    the month as number without a leading zero (1-12)
#  MM    the month as number with a leading zero (01-12)
#  MMM    the abbreviated localized month name (e.g. 'Jan' to 'Dec').
#  MMMM    the long localized month name (e.g. 'January' to 'December').
#  yy    the year as two digit number (00-99)
#  yyyy    the year as four digit number
#  For example, given the date of 9 Jan 2010, the following formats show
#  MMM yyyy ==> Jan 2010    yyyy ==> 2010       dd MMM yyyy ==> 09 Jan 2010
#  MM/yyyy ==> 01/2010      d/M/yy ==> 9/1/10   yy ==> 10
# publication default if not set: MMM yyyy
# timestamp default if not set: dd MMM yyyy
gui_pubdate_display_format = 'MMM yyyy'
gui_timestamp_display_format = 'dd MMM yyyy'

You want
gui_pubdate_display_format = 'yyyy'

ah cool, thanks!
You guys are brilliant!